US4825869A - System for automatically performing a clinical assessment of an implanted pacer based on information that is telemetrically received - Google Patents

System for automatically performing a clinical assessment of an implanted pacer based on information that is telemetrically received Download PDF

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US4825869A
US4825869A US07/101,757 US10175787A US4825869A US 4825869 A US4825869 A US 4825869A US 10175787 A US10175787 A US 10175787A US 4825869 A US4825869 A US 4825869A
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pacer
information
automatically
event
cardiac
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Louis Sasmor
Edward D. Smith
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Pacesetter Inc
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Telectronics NV
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Assigned to TELECTRONICS PACING SYSTEMS, INC. reassignment TELECTRONICS PACING SYSTEMS, INC. ASSIGNORS HEREBY CONFIRMS THE ENTIRE INTEREST IN SAID INVENTIONS TO ASSIGNEE ELECUTED ON SEPT. 16, 1988 (SEE RECORD FOR ETAILS). Assignors: CORDIS LEADS, INC., MEDICAL TELECTRONICS HOLDING & FINANCE CO., TELECTRONIC NV, TELECTRONICS PTY. LTD., TPL-CORDIS, INC.
Assigned to TELECTRONICS PACING SYSTEMS, INC. reassignment TELECTRONICS PACING SYSTEMS, INC. CORRECTIVE ASSIGNMENT TO CORRECT ASSIGNEE'S STATE OF INCORPORATION. AN ASSIGNMENT WAS PREVIOUSLY RECORDED AT REEL 6172, FRAME 0028. Assignors: CORDIS LEADS, INC., A DE COMPANY, MEDICAL TELECTRONICS HOLDING & FINANCE CO. (BV), A DUTCH COMPANY, TELECTRONICS NV, A COMPANY OF THE NETHERLANDS ANTILLES, TELECTRONICS PTY. LTD., AN AUSTRALIAN COMPANY, TPL-CORDIS, INC., A DELAWARE COMPANY
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    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61NELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00Electrotherapy; Circuits therefor
    • A61N1/18Applying electric currents by contact electrodes
    • A61N1/32Applying electric currents by contact electrodes alternating or intermittent currents
    • A61N1/36Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
    • A61N1/372Arrangements in connection with the implantation of stimulators
    • A61N1/37211Means for communicating with stimulators
    • A61N1/37252Details of algorithms or data aspects of communication system, e.g. handshaking, transmitting specific data or segmenting data
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61NELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00Electrotherapy; Circuits therefor
    • A61N1/18Applying electric currents by contact electrodes
    • A61N1/32Applying electric currents by contact electrodes alternating or intermittent currents
    • A61N1/36Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
    • A61N1/372Arrangements in connection with the implantation of stimulators
    • A61N1/37211Means for communicating with stimulators
    • A61N1/37235Aspects of the external programmer
    • A61N1/37247User interfaces, e.g. input or presentation means
    • GPHYSICS
    • G16INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR SPECIFIC APPLICATION FIELDS
    • G16HHEALTHCARE INFORMATICS, i.e. INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR THE HANDLING OR PROCESSING OF MEDICAL OR HEALTHCARE DATA
    • G16H10/00ICT specially adapted for the handling or processing of patient-related medical or healthcare data
    • G16H10/60ICT specially adapted for the handling or processing of patient-related medical or healthcare data for patient-specific data, e.g. for electronic patient records
    • G16H10/65ICT specially adapted for the handling or processing of patient-related medical or healthcare data for patient-specific data, e.g. for electronic patient records stored on portable record carriers, e.g. on smartcards, RFID tags or CD
    • GPHYSICS
    • G16INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR SPECIFIC APPLICATION FIELDS
    • G16HHEALTHCARE INFORMATICS, i.e. INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR THE HANDLING OR PROCESSING OF MEDICAL OR HEALTHCARE DATA
    • G16H15/00ICT specially adapted for medical reports, e.g. generation or transmission thereof
    • GPHYSICS
    • G16INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR SPECIFIC APPLICATION FIELDS
    • G16HHEALTHCARE INFORMATICS, i.e. INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR THE HANDLING OR PROCESSING OF MEDICAL OR HEALTHCARE DATA
    • G16H40/00ICT specially adapted for the management or administration of healthcare resources or facilities; ICT specially adapted for the management or operation of medical equipment or devices
    • G16H40/60ICT specially adapted for the management or administration of healthcare resources or facilities; ICT specially adapted for the management or operation of medical equipment or devices for the operation of medical equipment or devices
    • G16H40/63ICT specially adapted for the management or administration of healthcare resources or facilities; ICT specially adapted for the management or operation of medical equipment or devices for the operation of medical equipment or devices for local operation
    • GPHYSICS
    • G16INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR SPECIFIC APPLICATION FIELDS
    • G16HHEALTHCARE INFORMATICS, i.e. INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR THE HANDLING OR PROCESSING OF MEDICAL OR HEALTHCARE DATA
    • G16H50/00ICT specially adapted for medical diagnosis, medical simulation or medical data mining; ICT specially adapted for detecting, monitoring or modelling epidemics or pandemics
    • G16H50/20ICT specially adapted for medical diagnosis, medical simulation or medical data mining; ICT specially adapted for detecting, monitoring or modelling epidemics or pandemics for computer-aided diagnosis, e.g. based on medical expert systems
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10STECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S706/00Data processing: artificial intelligence
    • Y10S706/902Application using ai with detail of the ai system
    • Y10S706/924Medical

Definitions

  • the present invention concerns a novel system for gathering and processing information for the purpose of determining whether or not an implanted cardiac pacer system is functioning properly.
  • Modern implanted cardiac pacers have the ability to telemeter information to an external programming and/or receiving unit. In this manner, certain information concerning the pacer's characteristics, including mode, rate, battery level, etc. can be obtained. It is very desirable to be able to determine whether the implanted pacer is functioning properly; specifically, to determine whether the implanted pacer is supporting the patient as expected, given the pacer therapy described and programmed by the implanting or patient follow-up clinician. It would be extremely desirable to have the ability to analyze complex pacemaker modified electrocardiograms (ECGs), determine problems, relate the problems to the specific causes, and have the ability to recommend clinically acceptable actions.
  • ECGs complex pacemaker modified electrocardiograms
  • a cardiac pacer analysis system which non-invasively performs a detailed analysis of the functional status of the entire implanted pacemaker/patient system, rather than merely providing an annotated display of the ECG.
  • the illustrative embodiment combines the surface ECG with telemetered atrial and ventricular ICEGs and activity indicators into a common structure for the simultaneous analyses of pacing antifacts to verify pacemaker output, of evoked potentials to verify capture, and of spontaneous cardiac activity to verify pacemaker sensing. It incorporates a detailed model of the specific pacemaker, and adjusts the actions of the model based on telemetered pacemaker programmed parameter values.
  • the illustrative embodiment analyzes the functions of and identifies problems with the entire pacemaker system, including the leads and the pacemaker's interactions with the patient. It combines the abnormal functionings observed on different beats into a structure of common underlying problem causes, using a knowledge base which includes both clinical and engineering expertise. It incorporates information stored in and telemetered from the pacemaker (such as lead location and implant date) as well as the telemetered results of automatically performed pacemaker measurements (such as battery voltage and lead impedance) in identifying problems.
  • the illustrative embodiment uses its clinically derived knowledge base plus patient and pacemaker information to recommend specific corrective actions that could be taken to rectify problems that have been identified.
  • the illustrative embodiment provides an English language annotated description of the analysis results, along with conventional graphics ECGs.
  • the illustrative embodiment receives data about the pacemaker and its interaction with the patient from both surface ECG signals and telemetric communications with the pacemaker.
  • the telemetered data include programmed parameter vales, atrial and ventricular intra-cardiac electrograms, pacemaker activity indicators, the results of automatically performed pacemaker measurements, and patient history informaation previously stored in the pacemaker. These data are combined with a pre-stored knowledge base which encompasses the functional characteristics of the implanted pacemaker and the clinical interpretation of paced cardiac events.
  • the illustrative embodiment uses these data as information about the specific pacemaker/patient interactions, and via a combination of digital signal processing, emulation (modeling) of the pacemaker functions, and application of published and rules-of-thumb heuristic clinical interpretations of paced cardiac events, produces a comprehensive analysis of a patient's pacemaker modified ECG. It identifies normal and abnormal functional events, and summarizes these for the clinician; for any abnormal events, it identifies probable causes and lists appropriate possible diagnostic and therapeutic procedures.
  • FIG. 1 is a block diagram of a cardiac pacer analysis system constructed in accordance with the principles of the present invention
  • FIG. 2 is a typical device hard copy output of the system of FIG. 1;
  • FIG. 3 illustrates the structure needed to implement the system of FIG. 1 in a microprocessor-based instrument
  • FIG. 4A illustrates a surface ECG
  • FIG. 4B illustrates a normal acceptable atrial ICEG signal
  • FIG. 4C illustrates an unacceptable atrial ICEG signal
  • FIG. 4D illustrates an unacceptable atrial ICEG signal
  • FIG. 4E illustrates an unacceptable atrial ICEG signal
  • FIG. 5A illustrates an atrial ICEG with a pacing spike and repolarization atrifact
  • FIG. 5B illustrates an atrial ICEG after removal of the spike and atrifact
  • FIG. 6 illustrates the identification of cardiac activity
  • FIG. 7 illustrates the event list formatting
  • FIG. 8 illustrates an example event list
  • FIG. 9 is an overall flow chart for the paced ECG event analysis unit
  • FIG. 10 is a flow chart showing the initialization step of the paced ECG analysis
  • FIG. 11 is a flow chart showing the missing event determination step of the paced ECG event analysis
  • FIG. 12 is a flow chart showing the updating step of the paced ECG event analysis
  • FIG. 13 is a flow chart showing the clinical analysis and advisor unit
  • FIG. 14 is a flow chart showing the data reduction and summarization step of the clinical analysis and adviser unit
  • FIG. 15A illustrates an event status summary record that would be produced for the surface ECG illustrated in FIG. 15B;
  • FIG. 15B is an illustration of a sample (stylized) surface ECG
  • FIG. 16 is a flow chart showing the problem identification step for the clinical analysis and advisor unit.
  • FIG. 17 is a flow chart showing the step of determining problem causes and providing clinical advice by the clinical analysis and advisor unit.
  • the cardiac pacing analysis system of the present invention is embodied in a device including five major functional units:
  • the device consists of five major functional units:
  • a signal receiving and storage unit 20 is provided.
  • the signal receiving and storage unit 20 accepts surface ECG and telemetrically transmitted information from the pacemaker and stores it for later use by the remaining units.
  • the next three units analyze the received information; the digital signal processing unit 22 identifies and characterizes the events in the received ECG data, the paced ECG event analysis unit 24 determines if the pacemaker functioned correctly at each event, and the clinical analysis and advisor unit 26 summarizes these results and identifies and observed problems and provides probable causes and possible corrective actions for them.
  • the final unit, the results output unit 28, presents the results of the analyses to the clinician.
  • FIG. 1 shows how the information flows among the five units of the device, while FIG. 2 shows a typical device hard copy output.
  • FIG. 3 shows the structure needed to implement the device in a microprocessor-based instrument.
  • the signal receiving and storage unit accepts and stores two types of information.
  • the first is an array of digital information transmitted from the pacemaker.
  • pacemaker programming information the specific programmed values of all the pacemaker's programmable parameters
  • pacemaker stored patient related information such as implant date, lead type and location, pre-implant symptoms, etc.
  • results of automatically performed pacemaker measurements such as lead impedance or battery level.
  • the second type of information is a predetermined length of N seconds (up to 30, 8 in preferred implementation) of synchronously sampled electrocardiographic signals, including atrial and ventricular intra-cardiac electrograms, a surface ECG signal, and pacemaker generated activity indicators (telemetered signals which identify specific actions taken by, or changes of state in, the implanted pacemaker, such as paced, sensed, end of refractory, etc.).
  • N seconds up to 30, 8 in preferred implementation
  • the atrial and ventricular intra-cardiac electrograms are sampled by the pacemaker, and digitally transmitted, along with the pacemaker activity indicators, to the device.
  • the surface ECG signal is presented to the device as an analog signal. The devide samples this synchronously with the intra-cardiac electrogram sampling by taking a surface ECG sample at the time of receipt of every other intra-cardiac electrogram sample.
  • the signal sampling sequence is: receive an atrial ICEG sample, receive a ventricular ICEG sample, take a surface ECG sample, receive an atrial ICEG sample, and so on.
  • the pacemaker activity indicators are transmitted by the pacemaker in lieu of ICEG samples, with a unique identifying code. Each activity indicator takes the place of one sample, so synchrony is maintained. (Note: The digital signal processing unit extracts each indicator from the ICEG data stream, and replaces the "missing" ICEG sample value with an interpolated value.
  • the pacemakeer stored information is received first, the the combined ICEG, ECG, and activity indicator signals. Processing of the information does not begin until all the signal information has been received and stored.
  • the received ECG/ICEG signals are displayed on a real time analog display for the operator, and are continuously stored in a circular buffer holding N seconds of the digitized signals. When the operator is satisfied with the received signals, he indicates this, and the last N seconds (stored in the buffer) are saved for analysis.
  • the purpose of the digital signal processing is to convert the continuous stream of digitized analog information into an ordered list of discrete events, and to characterize each event.
  • An event is defined as any interaction between the pacemaker and the heart, or any cardiac activity which should have caused a pacemaker response. These include (for either channel) spontaneous cardiac activity (whether sensed or not), pacemaker sensing of cardiac activity (whether of valid signal or of noise), pacemaker pacing outputs and cardiac evoked responses.
  • An event is characterized by a set of quantitative and symbolic metrics, including the time of occurrence, the channel on which it occurred, the presence or absence of spontaneous activity, whether or not the pacemaker sensed, and/or claimed (as shown by an activity indicator) it output a packing pulse, the presence or absence of a pacing pulse in the ECG signals, and the presence or absence of an evoked response.
  • an activity indicator for example, an PVC indication
  • pacemaker state changes which were signaled by an activity indicator (such as the end of a channel's refractory period) are identified, but not as separate events. Every event has appended to it a series of occurrence times, one for each possible pacemaker state change. If a particular state change happened between two events (after event A, but before event B) its time of occurrence in the description of the present event (event A) is set to a positive number, indicating how many milliseconds after the present event it occurred. A time of zero is used to indicate that no such change occurred between the present event and the next one.
  • the digital signal processing performs a six step process, as follows:
  • the sampled ICEG signals and the pacemaker activity indicators are received as a single multiplexed data stream. This is separated into three signals: the atrial ICEG, the ventricular ICEG, and the activity indicators. This is accomplished based on the known transmission sequence used by the pacemaker, and the unique codes which identify the activity indicators.
  • the ICEG signal timing will be corrected for any missing or time-shifted samples.
  • the atrial and ventricular ICEG samples are taken alternately, and the surface ECG samples are taken synchronously with every other transmitted sample (or inserted activity indicator), all sampled data and activity indicators must be corrected to produce a common sampling moment. These two steps are accomplished simultaneously.
  • the result of this step is a set of four synchronously sampled signals; the surface ECG, the atrial and ventricular ICEGs, and the activity indicators.
  • the received signals are sorted and corrected as indicated in the following Chart A:
  • ECG and both ICEG signals are checked to determine if they are "clean" enough for processing.
  • the average and deviation of the signals are checked to determine if the overall signal level and the signal to noise level of each is acceptable, and each signal is checked for amplifier saturation following pacemaker output spikes.
  • FIGS. 4A-4E show examples of acceptable and unacceptable Atrial ICEG signals, with the surface ECG included for reference only. The signals shown are idealized versions for illustrative purposes; they are not real human data.
  • This step in the process locates and removes from each signal channel the pacing "spikes" and polarization artifacts caused by pacemaker outputs. This enhances the later identification of cardiac activity (either spontaneous or evoked).
  • Pacing spikes are identified in each channel by the presence of threshold crossings in the signal's derivative with a specified time relationship, based on the known pacemaker output pulse width. These spikes are then matched to pacemaker output activity indicators to determine on which channel the pacemaker output occurred. The time channel and occurrence for each pacing spike is stored, and all the pacing spikes are then removed, with a different method used for each channel.
  • the pacemaker spiked are removed from the surface channel by subtraction, and then the surface ECG signal is smoothed, by interpolation, to follow the "surrounding" evoked response.
  • Pacemaker spikes and polarization artifacts are removed from the channel on which the pacing spike occurred in a two step process. First, the pacing spike itself is subtracted. Next, the polarization atrifact is exponentially approximated using a second order linear predictor with a least squares estimator; this exponential is then subtracted. This allows the evoked response to be retained, even through it occurs in the middle of the exponential polarization atrifact.
  • pacing spikes due to pacemaker outputs on one channel are similarly removed from the other ICEG channel.
  • large "far field” polarization artifacts seen in the atrial channel due to ventricular outputs are exponentially removed.
  • FIGS. 5A-5B illustrate this process.
  • FIG. 5A shows a sampled ICEG (idealized) including a pacing spike and a repolarization atrifact.
  • FIG. 5B shows the results of subtracting the pacing spike and the exponentially approximated repolarization atrifact. The remaining signal (shown as a sine wave) would represent the cardiac activity.
  • Cardiac activity (either spontaneous or evoked) is detected via a two-step process.
  • a simple detector scans each signal channel for possible areas of activity.
  • a "smart" detector scans all three signals simultaneously, looking at each area identified by the simple detector.
  • the simple detector uses a level threshold to locate areas of possible cardiac activity. It independently scans each signal channel (surface ECG, atrial ICEG, and ventricular ICEG) to locate areas where the signal exceeds a defined threshold. The threshold is determined for each channel based on the mean, deviation, and peak values of the signal in that channel. The locations of these "candidate” areas are stored for use by the "smart” detector. (The primary purpose of this "simple” detector is to reduce the amount of signal the computationally intensive "smart” detector must process.)
  • the smart detector uses a set of "expectancy" matrices. These prestored matrices essentially contain what the device "expects” each type of event (atrial activity, ventricular activity, and noise) to look like across all three channels over a small sequence of samples. They were obtained by taking the mathematical inverse of "observed” signal matrices. The "observed” matrices were based on the combination of a large number of observations of each type of activity.
  • the "smart” detector scans each type of expectancy matrix across all three simultaneous signals for each area identified by the “simple” detector, determining a "detector output” for each point in the candidate area. It also determines the first and second moment of the detector output. Based on these results, it selects the most probable identification of each candidate area (atrial activity, ventricular activity, or noise) and identifies the fiducial point (or common time reference point) for each area identified as cardiac activity.
  • FIG. 6 illustrates this process.
  • the upper section shows three (stylized) simultaneous data signals--the surface ECG, the atrial ICEG, and the ventricular ICEG. Immediately below each signal are indicated the "Candidate" areas identified by independently scanning each signal with the simple detector.
  • the lower section shows the output of each of the smart detectors over each identified candidate area. These are obtained by independently scanning each smart detector over all three data signals simultaneously. Note that the outputs of the smart detectors exist only for simple detector identified candidate areas.
  • the bottom line indicates the decision made about each candidate area, based on the relative outputs of the smart detectors.
  • Each candidate area is identified as either atrial activity, ventricular activity, or noise (no cardiac activity).
  • This step examines each identified occurrence of cardiac activity and attempts to associate it with a previously identified pacemaker action (such as a sense or a pace). For example, cardiac activity on a particular channel immediately following a pacemaker output on that channel would be considered as an evoked response, and would be evidence that the pacemaker output had "captured" the chamber. Those occurrences of cardiac activity which cannot be associated with an appropriate pacemaker activity indicator are retained as separate events. An example of this would be an unsensed P wave.
  • the last step in the digital signal processing unit is to sequentially sort the identified events, and to write them in a standard format into the "event list". It is this list of discrete events that will be analyzed by the paced ECG event analysis unit.
  • FIG. 7 shows the (stylized) surface ECG and the activity indicators for that section of the data.
  • FIG. 8 is an event list corresponding to the data section of FIG. 7.
  • the purpose of the paced ECG event analysis unit is to examine each individual event and determine if the pacemaker functioned properly. For example, did it sense (or not sense) spontaneous cardiac activity when it was supposed to, did it output a pacing pulse at the correct time, did the pacing pulse capture the heart (produce an evoked response in the paced chamber), did the refractory periods end on time, were there any occurrences of PVCs, PACs, or special pacemaker mediated events, etc.
  • each event is analyzed, several status indicators are determined for each event. These include sensing status, pacing (timing) status, capture status, state change timing (such as end of refractory period) status, and special (PVC, anti-PMT dropped beat, ventricular safety pace beat, etc.) statuses.
  • the possible values for each status indicator include all possible normal and abnormal functional conditions for that pacemaker function. For example, the possible values for sensing status include three normal conditions (OK) and five abnormal conditions (NG), as follows:
  • the unit Since is is possible for several abnormal conditions to occur at the same time (for example, an oversense in the blanking period), the unit identifies the most serious problem, and assigns that status indicator value for the event.
  • the paced ECG event analysis unit is based on a detailed model of the functioning relationships incorporated in the pacemaker's hardware and software, expressed as a set of logical rules. These rules predict exactly what the pacemaker is expected to do in any situation, based on the programmed parameter values.
  • the unit compares the expected functioning (as predicted by the model) with the observed functioning (as evidenced by the event list) to determine the status of each pacemaker function for each event.
  • the paced ECG event analysis unit performs a five step process, with the last four steps repeated sequentially for each entry in the event list, as follows:
  • FIG. 9 shows the overall flow of information in this unit.
  • the pacemaker In order to determine how the pacemaker should act at a given moment it is necessary to know the "state" of the pacemaker; i.e., the value of every variable in the pacemaker at that moment in time. For example, to determine if the pacemaker should sense a P-wave, it is necessary to know if atrial sensing is on or off, and, if it is on, is the channel blanked, refractory, alert, or in a noise window. The values of these internal pacemaker variables depend on both the programmed parameter values and the past experience (history) of the pacemaker. While all programmed parameter values are known, the history of the pacemaker is not known at the beginning of the ECG/ICEG data segment. Initialization establishes its state.
  • Initialization is accomplished by assuming that the pacemaker is functioning properly, and examining how it acted in response to the heart's actions early on in the data segment. For example, if a DDD pacemaker's first action was to pace the atrium, then it is assumed to have been in the atrial escape interval at the start of the data segment. Since both the number of possible pacemaker states and the number of first actions are finite (though large), an exhaustive analysis of the responses to initial actions allows the pacemaker's state at the start of the data to be uniquely determined. Once the initial state of the pacemaker has been determined, each subsequent event can then be sequentially analyzed. FIG. 10 shows the sequence of information flow for this unit.
  • each event begins by checking to see if any event should have occurred after the last analyzed event and prior to the specific event that is about to be analyzed; i.e., is any expected event "missing.” This can occur for two reasons, pacemaker malfunction or unobserved pacemaker state changes. If a "missing event" is identified, it is inserted into the event list ahead of the event about to be analyzed. The inserted "missing" event will be analyzed next, before the event that was about to be analyzed. Examples of each type of "missing event” follow. FIG. 11 shows the decision structure for identifying "missing" events.
  • a VOO pacemaker is programmed to 60 beats per minute, and that the interval from the previous event (a ventricular pace) to the event about to be analyzed in the event list is 1,200 milliseconds.
  • the pacemaker should have output a pulse 1,000 milliseconds after the previous event, and did not--it malfunctioned. This is accommodated by adding an event to the event list at 1,000 milliseconds after the previous event (200 milliseconds before the event that was about to be analyzed). When this "added" event is analyzed, it will indicate a failure to pace when expected.
  • missing events can also occur during normal pacemaker functioning. For example, consider a VDD pacemaker. Assume that following a ventricular pace, no atrial activity is detected for the entire minimum rate determined beat to beat interval. The pacemaker would then correctly pace the ventricle. However, the atrial escape interval has ended and the ventricular escape interval (or AV delay) has started with no activity indicator. To allow the model to correctly process this state change, an event would be added to the event list at the expected end of the atrial escape interval. (This is identified as a "phantom" event and is only used internally for analysis; it is not identified as an event to the user.)
  • the rules used are based on a rigorous, exhaustive analysis of all possible combinations of relevant event metrics and pacemaker programmed parameter values, and were verified by clinical experts.
  • the rules are independent of the channel where the event occurred, except for events such as premature ventricular contractions or retrograde P waves, which can occur only on a specific channel.
  • Each event may change the state of the pacemaker. This will affect the way in which it responds to the next event.
  • This step in the paced ECG event analysis determines the way in which the state of the pacemaker has been changed by the event just analyzed. In essence, it "updates" the running model of the pacemaker, and prepares it to evaluate the next event.
  • Chart B shows the input variables used by, and the possible outcomes for, each set of event status determination rules--sensing, pacing (timing) and capture. Note that the same rules apply to both the atrial and ventricular channels, and are applied independently to each.
  • the duration of the AV delay may be a function of whether or not the two previous atrial events were paced or sensed. If this is not shown (such as on the second beat), the model would be updated to show a range of allowable AV delays, based on however much history is known. When the next ventricular event is analyzed, AV delays falling anywhere in this range would be considered correct functioning.
  • FIG. 12 shows the steps involved in updating the pacemaker model, depending on the type of event that has occurred. Note that the process is similar, regardless of the channel on which the event occurred.
  • Certain state changes within the pacemaker are signaled by telemetered activity indicators, but are not considered as pacemaker/patient events. They were indicated in the event list by noting the time they occurred after the immediately preceding true event. The last step in the analysis of a single event is to look for any such indicators and verify their function and timing.
  • the following Chart C shows the input variables and possible outcomes for a typical state change activity indicator status determination, the end of refractory period activity indicator. Note that the same rules apply to both the atrial and ventricular channels, and are applied independently to each.
  • the purpose of the clinical analysis and advisor unit is to combine the results of the analyses of the individual events into a single comprehensive evaluation of the implanted cardiac pacemaker system.
  • the event list contains the signal analysis metrics and statuses for each patient/pacemaker interaction or event.
  • the clinical analysis and advisor unit uses expert system techniques to combine the information in the event list with patient and pacemaker data, and a knowledge base of clinical expertise in ECG problem solving to produce a summary analysis of the functional condition of the implanted pacemaker; including any identified problem(s), their probable cause(s), and clinically acceptable actions to correct them.
  • the clinical analysis and advisor unit uses a clinical knowledge base organized into a series of frame-like structures; that is, separate structures for problems relating to pacing leads, pacing rate, pacemaker electronic malfunctions, pacing and sensing thresholds, pacing lead configurations, etc. This allows the unit to search the knowledge base much as a clinician would analyze a paced ECG in actual practice.
  • This structuring also allows each step of the analysis to be individually examined and validated. Because each structure covers a limited and defined domain (set of possible inputs, problems, and causes) it can be rigorously validated, often by exhaustive search of all possible input combinations and their resulting outputs. This is typically not possible in most expert systems which do not employ such a frame-like structuring.
  • the clinical analysis and advisor unit uses a four step process, as follows:
  • FIG. 13 shows the sequence of events in this unit.
  • steps three and four of this process were combined into a single step. Therefore, in the following descriptions, the purposes of these last two steps will be separately described, and then their implementation as a single step will be described.
  • the number of programmable parameter values stored in the pacemaker can cause a combinatorial explosion, results in an unmanageable number of logic tests being needed to arrive at a single analysis result.
  • These programmable parameter values are reduced to a manageable number by symbolic representations.
  • a pacemaker may have up to 128 possible combinations for pacemaker output amplitude and pulse width. This is first reduced by combining the two values into a single value representing the total charge delivered by the output. This might reduce the 128 values by more than half. Next these charge values are ordered and identified as falling into one of five clinically significant symbolically labelled categories.
  • a set of 40 charge values might be labelled as follows:
  • the second data reduction is performed primarily to reduce the amount of information that will have to be presented to the clinician. Separate events are combined into larger P-QRS complexes identified as "beats." This allows the conversion of references from the exact time domain into the clinical terms normally used in discussing ECGs. Thus, rather than reporting an atrial event which occurred at 2895 milliseconds into the data segment, the device can refer to the atrial part of P-QRS beat 3. This reduction is accomplished by a set of rules that examine the order and type of atrial and ventricular events within specific time limits.
  • Productions are also used to combine the order and timing of individual events to identify ECG occurrences that happen over several beats, such as retrograde P waves, premature ventricular contractions, or pacemaker mediated tachycardia. These identifications are added to the individual event descriptions in the Event List before summarization.
  • FIG. 14 shows the sequential flow of these activities.
  • FIG. 15 shows the event status summary record that would be produced for the sample (stylized) surface ECG shown in FIG. 15B. The record is based on the analysis of all the signals, not just the surface ECG. The surface ECG is included here for illustrative purposes only.
  • the event status summary record is produced, it is scanned via a computed "key” access (based on the channel, the number of records, and status indicator) to the record, to determine the operational status of each of the pacemaker's functions (sensing, pacing, timing and capture) for each channel.
  • the productions examine the status indicator values for each particular function for all events. Functions are identified as having one of four operational states, as follows:
  • Abnormal-Intermittent The particular function was observable at least twice during the ECG data segment; its status was OK at least once and No Good at least once. (Example: Multiple paced atrial beats, with the atrium captured on some beats and not on others.)
  • Abnormal--Complete (or Constant): The particular function was observable at least once during the ECG data segment; its status was No Good every time it was observed. (Example: One or more paced atrial beats, none of which captured the atrium.)
  • the device has simply "reviewed” the ECG and "reported” its findings, "flagging” any abnormalities. There has been no identification of the possible causes of any of the observed abnormalities, and no determination of future clinical actions, either diagnostic or therapeutic. In certain applications, this would be the appropriate termination of the analysis. In those cases, the remaining stages in the clinical analysis and advisor unit would be disabled, and the present coded analysis results would be directly passed to the results output unit.
  • FIG. 16 shows the sequential identification of problems with each of the different pacer functions.
  • the device must determine what caused the problem(s). Because of the complex interactions within the implanted system, multiple observed problems may in fact have a common cause. For example, a dislodged atrial lead could cause both intermittent atrial under sensing and complete loss of atrial capture; in the presence of retrograde conduction, this could also yield retrograde P waves. Alternately, consistent atrial undersensing along with complete loss of atrial capture could be due to an atrial lead problem (fracture, dislocation, etc.) or to separately programmed inappropriate values for atrial output and atrial sensitivity.
  • Problem causes are grouped by engineering system (pacemaker timing control, output circuits, sensing circuits, leads, etc.), with each system being sequentially examined.
  • the stored knowledge base used to identify problem causes is based upon a structured representation of information derived primarily from pacemaker system engineers, and secondarily from experienced clinicians, obtained through both reviews of published material and extensive interviews.
  • Another knowledge base (obtained primarily from clinical experts) is used to identify appropriate and generally accepted clinical procedures. These may include both specific actions (such as reprogramming the pacemaker) and diagnostic procedures (such as fluoroscopic examination of the lead).
  • the recommendations are based not only on the observed problem, but also on stored information about the pacemaker and the patient. For example, increasing the pacemaker's output would not be recommended if the pacemaker were already at maximum output, while reducing the pacing rate to attempt to observe atrial sensing would not be recommended if the patient has a pre-pacing history of syncope.
  • the device In addition to identifying possible actions, the device also identifies specific facts from the stored information which are relevant to the actions identified. These are passed to the results output unit along with the actions.
  • the two separate steps of determination of problem causes the provision of clinical advice have been combined into a single step.
  • the two separate knowledge bases were combined into a common sets of productions with a single inference engine.
  • FACTS are the combinations of symbolic representations of the stored pacemaker data, quantitative and symbolic paced ECG event metrics, and the summary of the statuses for each event.
  • Each "FACTS” part of a production essentially represents a possible problem state.
  • the "ACTION” part of a production contains relevant pacemaker programmed variables to be displayed, a statement of both normal and abnormal events and where they occur (P-QRS beats), the probable cause of the abnormal event, some reasoning about the event (if possible) and recommendations for actions to correct the problem.
  • the productions are grouped (framed) into problem categories. That is: pacemaker malfunctioning, pacing leads, pacing and sensing thresholds, pacing rate, etc.
  • the mechanism to search through the entire knowledge base of productions is called an "inference engine.” Each production is examined, and if the "FACTS" part is true, then the production is instantiated and the "ACTIONS" occur. If false, then the search continues to process the other productions.
  • the order of the search through the productions emulates the way in which a clinician would view and analyze a patient's paced ECG.
  • FIG. 17 shows the structure of the Expert System that is used for the joint implementation of these two steps, indicating the types of information stored in each section of the data base.
  • results output unit The purpose of the results output unit is to present the conclusions from the analyses to the clinician. Depending on the capabilities of the output unit, results may be presented either as a single entity or as a sequential series of presentations, either on a visual display or in "hard copy.”
  • the results output unit performs several functions. First, it combines the stored surface ECG with the derived beat identifications and stored activity indicators to provide an annotated ECG. Second, it provides a display of the summarized results for each channel, identifying all observed and unobserved functional status for each channel, with all abnormal findings clearly labelled. Finally, for every abnormal finding, it lists the relevant pacemaker and patient data, the probable causes, and possible corrective actions.
  • This unit includes large scale editing and code conversion sections, to convert the internal coded information into specific user readable outputs, tailored to the specific display being used, as well as the connectors and drivers for the actual output unit employed.

Abstract

A cardiac pacer analysis system which is external to the patient is provided for an implanted pacer having patient history stored within the pacer. Information is transmitted from the pacer, and is received, stored and processed. Events in the received information are identified and characterized, observed problems are identified, probable causes of observed problems are indicated and possible corrective actions are provided. The results of the analyses are displayed for the clinician.

Description

FIELD OF THE INVENTION
The present invention concerns a novel system for gathering and processing information for the purpose of determining whether or not an implanted cardiac pacer system is functioning properly.
BACKGROUND OF THE INVENTION
Modern implanted cardiac pacers have the ability to telemeter information to an external programming and/or receiving unit. In this manner, certain information concerning the pacer's characteristics, including mode, rate, battery level, etc. can be obtained. It is very desirable to be able to determine whether the implanted pacer is functioning properly; specifically, to determine whether the implanted pacer is supporting the patient as expected, given the pacer therapy described and programmed by the implanting or patient follow-up clinician. It would be extremely desirable to have the ability to analyze complex pacemaker modified electrocardiograms (ECGs), determine problems, relate the problems to the specific causes, and have the ability to recommend clinically acceptable actions.
SUMMARY OF THE INVENTION
In accordance with the present invention, a cardiac pacer analysis system is provided which non-invasively performs a detailed analysis of the functional status of the entire implanted pacemaker/patient system, rather than merely providing an annotated display of the ECG. The illustrative embodiment combines the surface ECG with telemetered atrial and ventricular ICEGs and activity indicators into a common structure for the simultaneous analyses of pacing antifacts to verify pacemaker output, of evoked potentials to verify capture, and of spontaneous cardiac activity to verify pacemaker sensing. It incorporates a detailed model of the specific pacemaker, and adjusts the actions of the model based on telemetered pacemaker programmed parameter values.
The illustrative embodiment analyzes the functions of and identifies problems with the entire pacemaker system, including the leads and the pacemaker's interactions with the patient. It combines the abnormal functionings observed on different beats into a structure of common underlying problem causes, using a knowledge base which includes both clinical and engineering expertise. It incorporates information stored in and telemetered from the pacemaker (such as lead location and implant date) as well as the telemetered results of automatically performed pacemaker measurements (such as battery voltage and lead impedance) in identifying problems.
The illustrative embodiment uses its clinically derived knowledge base plus patient and pacemaker information to recommend specific corrective actions that could be taken to rectify problems that have been identified.
The illustrative embodiment provides an English language annotated description of the analysis results, along with conventional graphics ECGs.
The illustrative embodiment receives data about the pacemaker and its interaction with the patient from both surface ECG signals and telemetric communications with the pacemaker. The telemetered data include programmed parameter vales, atrial and ventricular intra-cardiac electrograms, pacemaker activity indicators, the results of automatically performed pacemaker measurements, and patient history informaation previously stored in the pacemaker. These data are combined with a pre-stored knowledge base which encompasses the functional characteristics of the implanted pacemaker and the clinical interpretation of paced cardiac events.
The illustrative embodiment uses these data as information about the specific pacemaker/patient interactions, and via a combination of digital signal processing, emulation (modeling) of the pacemaker functions, and application of published and rules-of-thumb heuristic clinical interpretations of paced cardiac events, produces a comprehensive analysis of a patient's pacemaker modified ECG. It identifies normal and abnormal functional events, and summarizes these for the clinician; for any abnormal events, it identifies probable causes and lists appropriate possible diagnostic and therapeutic procedures.
A more detailed explanation of the invention is provided in the following descriptions and claims, and is illustrated in the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of a cardiac pacer analysis system constructed in accordance with the principles of the present invention;
FIG. 2 is a typical device hard copy output of the system of FIG. 1;
FIG. 3 illustrates the structure needed to implement the system of FIG. 1 in a microprocessor-based instrument;
FIG. 4A illustrates a surface ECG;
FIG. 4B illustrates a normal acceptable atrial ICEG signal;
FIG. 4C illustrates an unacceptable atrial ICEG signal;
FIG. 4D illustrates an unacceptable atrial ICEG signal;
FIG. 4E illustrates an unacceptable atrial ICEG signal;
FIG. 5A illustrates an atrial ICEG with a pacing spike and repolarization atrifact;
FIG. 5B illustrates an atrial ICEG after removal of the spike and atrifact;
FIG. 6 illustrates the identification of cardiac activity;
FIG. 7 illustrates the event list formatting;
FIG. 8 illustrates an example event list;
FIG. 9 is an overall flow chart for the paced ECG event analysis unit;
FIG. 10 is a flow chart showing the initialization step of the paced ECG analysis;
FIG. 11 is a flow chart showing the missing event determination step of the paced ECG event analysis;
FIG. 12 is a flow chart showing the updating step of the paced ECG event analysis;
FIG. 13 is a flow chart showing the clinical analysis and advisor unit;
FIG. 14 is a flow chart showing the data reduction and summarization step of the clinical analysis and adviser unit;
FIG. 15A illustrates an event status summary record that would be produced for the surface ECG illustrated in FIG. 15B;
FIG. 15B is an illustration of a sample (stylized) surface ECG;
FIG. 16 is a flow chart showing the problem identification step for the clinical analysis and advisor unit; and
FIG. 17 is a flow chart showing the step of determining problem causes and providing clinical advice by the clinical analysis and advisor unit.
DETAILED DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENT
Referring to FIG. 1, the cardiac pacing analysis system of the present invention is embodied in a device including five major functional units:
The device consists of five major functional units:
1. A signal receiving and storage unit 20,
2. A digital signal processing unit 22,
3. A paced ECG event analysis unit 24,
4. A clinical analysis and advisor unit 26, and
5. A results output unit 28.
The signal receiving and storage unit 20 accepts surface ECG and telemetrically transmitted information from the pacemaker and stores it for later use by the remaining units. The next three units analyze the received information; the digital signal processing unit 22 identifies and characterizes the events in the received ECG data, the paced ECG event analysis unit 24 determines if the pacemaker functioned correctly at each event, and the clinical analysis and advisor unit 26 summarizes these results and identifies and observed problems and provides probable causes and possible corrective actions for them. The final unit, the results output unit 28, presents the results of the analyses to the clinician.
FIG. 1 shows how the information flows among the five units of the device, while FIG. 2 shows a typical device hard copy output. FIG. 3 shows the structure needed to implement the device in a microprocessor-based instrument.
SIGNAL RECEIVING AND STORAGE UNIT 20
The signal receiving and storage unit accepts and stores two types of information.
The first is an array of digital information transmitted from the pacemaker. This includes pacemaker programming information (the specific programmed values of all the pacemaker's programmable parameters), pacemaker stored patient related information (such as implant date, lead type and location, pre-implant symptoms, etc.), and results of automatically performed pacemaker measurements (such as lead impedance or battery level).
The second type of information is a predetermined length of N seconds (up to 30, 8 in preferred implementation) of synchronously sampled electrocardiographic signals, including atrial and ventricular intra-cardiac electrograms, a surface ECG signal, and pacemaker generated activity indicators (telemetered signals which identify specific actions taken by, or changes of state in, the implanted pacemaker, such as paced, sensed, end of refractory, etc.).
The atrial and ventricular intra-cardiac electrograms are sampled by the pacemaker, and digitally transmitted, along with the pacemaker activity indicators, to the device. The surface ECG signal is presented to the device as an analog signal. The devide samples this synchronously with the intra-cardiac electrogram sampling by taking a surface ECG sample at the time of receipt of every other intra-cardiac electrogram sample. The signal sampling sequence is: receive an atrial ICEG sample, receive a ventricular ICEG sample, take a surface ECG sample, receive an atrial ICEG sample, and so on.
The pacemaker activity indicators are transmitted by the pacemaker in lieu of ICEG samples, with a unique identifying code. Each activity indicator takes the place of one sample, so synchrony is maintained. (Note: The digital signal processing unit extracts each indicator from the ICEG data stream, and replaces the "missing" ICEG sample value with an interpolated value.
The pacemakeer stored information is received first, the the combined ICEG, ECG, and activity indicator signals. Processing of the information does not begin until all the signal information has been received and stored. The received ECG/ICEG signals are displayed on a real time analog display for the operator, and are continuously stored in a circular buffer holding N seconds of the digitized signals. When the operator is satisfied with the received signals, he indicates this, and the last N seconds (stored in the buffer) are saved for analysis.
DIGITAL SIGNAL PROCESSING UNIT 22
The purpose of the digital signal processing is to convert the continuous stream of digitized analog information into an ordered list of discrete events, and to characterize each event.
An event is defined as any interaction between the pacemaker and the heart, or any cardiac activity which should have caused a pacemaker response. These include (for either channel) spontaneous cardiac activity (whether sensed or not), pacemaker sensing of cardiac activity (whether of valid signal or of noise), pacemaker pacing outputs and cardiac evoked responses.
An event is characterized by a set of quantitative and symbolic metrics, including the time of occurrence, the channel on which it occurred, the presence or absence of spontaneous activity, whether or not the pacemaker sensed, and/or claimed (as shown by an activity indicator) it output a packing pulse, the presence or absence of a pacing pulse in the ECG signals, and the presence or absence of an evoked response. In addition, any other "special" information conveyed by the activity indicators (for example, an PVC indication) is included in the event description.
The presence of other pacemaker state changes which were signaled by an activity indicator (such as the end of a channel's refractory period) are identified, but not as separate events. Every event has appended to it a series of occurrence times, one for each possible pacemaker state change. If a particular state change happened between two events (after event A, but before event B) its time of occurrence in the description of the present event (event A) is set to a positive number, indicating how many milliseconds after the present event it occurred. A time of zero is used to indicate that no such change occurred between the present event and the next one.
The digital signal processing performs a six step process, as follows:
1. Signal sorting, activity indicator identification and removal,
2. ECG (including ICEG) signal verification,
3. Identification and removal of pacing spikes and atrifacts,
4. Detection of cardiac activity,
5. Correlation of cardiac activity and pacing spikes with activity indicators, and
6. Formatting the event list (for further analysis).
SIGNAL SORTING, ACTIVITY INDICATOR IDENTIFICATION AND REMOVAL
The sampled ICEG signals and the pacemaker activity indicators are received as a single multiplexed data stream. This is separated into three signals: the atrial ICEG, the ventricular ICEG, and the activity indicators. This is accomplished based on the known transmission sequence used by the pacemaker, and the unique codes which identify the activity indicators.
Next, since activity indicators are transmitted in place of ICEG signal samples, the ICEG signal timing will be corrected for any missing or time-shifted samples. In addition, since the atrial and ventricular ICEG samples are taken alternately, and the surface ECG samples are taken synchronously with every other transmitted sample (or inserted activity indicator), all sampled data and activity indicators must be corrected to produce a common sampling moment. These two steps are accomplished simultaneously. The result of this step is a set of four synchronously sampled signals; the surface ECG, the atrial and ventricular ICEGs, and the activity indicators. The received signals are sorted and corrected as indicated in the following Chart A:
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CHART A                                                                   
Signal Sorting, Activity Indicator Identification and Removal             
__________________________________________________________________________
A. ICEG and ECG Signals as Received                                       
(Assuming 500 sample per second for each signal)                          
Time (msec)                                                               
       1  2  3   4   5  6  7  8  9  10 11 12                              
       |                                                         
          |                                                      
             |                                                   
                 |                                               
                     |                                           
                        |                                        
                           |                                     
                              |                                  
                                 |                               
                                    |                            
                                       |                         
                                          |                      
Telemetry                                                                 
       DA1                                                                
          DV1                                                             
             DA2 DV2 DA3                                                  
                        DV3                                               
                           DA4                                            
                              PI1                                         
                                 DA5                                      
                                    DV5                                   
                                       DA6                                
                                          DV6                             
       |                                                         
          |                                                      
             |                                                   
                 |                                               
                     |                                           
                        |                                        
                           |                                     
                              |                                  
                                 |                               
                                    |                            
                                       |                         
                                          |                      
Surface ECG                                                               
          S1     S2     S3    S4    S5    S6                              
Where D and P are unique code indentifiers for ICEG data samples          
and pacemaker activity indicators, respectively;                          
A1, V1, and S1 are sample number 1 of the Atrial ICEG,                    
Ventricular ICEG, and Surface ECG signals, repectively;                   
and I1 is the code for the pacemaker activity indicator number            
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B. Stored Uncorrected Signal Data Files                                   
Time      A ICEG                                                          
               V ICEG       S ECG                                         
                                Act. Ind.                                 
__________________________________________________________________________
1         A1   --           --  --                                        
2         --   V1           S1  --                                        
3         A2   --           --  --                                        
4         --   V2           S2  --                                        
5         A3   --           --  --                                        
6         --   V3           S3  --                                        
7         A4   --           --  --                                        
8         --   --           S4  I1                                        
9         A5   --           --  --                                        
10        --   V5           S5  --                                        
11        A6   --           --  --                                        
12             V6           S6  --                                        
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C. Stored Corrected Signal Data Files                                     
After Interpolation of V4, which was missing because of I1,               
and Correction of Atrial ICEG to Common Sampling Time)                    
Time      A ICEG                                                          
               V ICEG       S ECG                                         
                                Act. Ind.                                 
__________________________________________________________________________
2         a1   V1           S1  --                                        
4         a2   V2           S2  --                                        
6         a3   V3           S3  --                                        
8         a4   V4           S4  I1                                        
10        a5   V5           S5  --                                        
12        a6   V6           S6  --                                        
__________________________________________________________________________
 Where a1 = (A1 + A2)/2 and V4 = (V3 +  V5)/2                             
ECG Signal Verification
Before any further processing, the ECG and both ICEG signals are checked to determine if they are "clean" enough for processing. The average and deviation of the signals are checked to determine if the overall signal level and the signal to noise level of each is acceptable, and each signal is checked for amplifier saturation following pacemaker output spikes.
If the signal is unsatisfactory, the user is informed (via the Results Output Unit) that the signal cannot be processed, and why. The device then stops and waits for the user to obtain another time segment of ECG/ICEG signals. FIGS. 4A-4E show examples of acceptable and unacceptable Atrial ICEG signals, with the surface ECG included for reference only. The signals shown are idealized versions for illustrative purposes; they are not real human data.
Identification and Removal of Pacing Spikes and Atrifacts
This step in the process locates and removes from each signal channel the pacing "spikes" and polarization artifacts caused by pacemaker outputs. This enhances the later identification of cardiac activity (either spontaneous or evoked).
Pacing spikes are identified in each channel by the presence of threshold crossings in the signal's derivative with a specified time relationship, based on the known pacemaker output pulse width. These spikes are then matched to pacemaker output activity indicators to determine on which channel the pacemaker output occurred. The time channel and occurrence for each pacing spike is stored, and all the pacing spikes are then removed, with a different method used for each channel.
The pacemaker spiked are removed from the surface channel by subtraction, and then the surface ECG signal is smoothed, by interpolation, to follow the "surrounding" evoked response.
Pacemaker spikes and polarization artifacts are removed from the channel on which the pacing spike occurred in a two step process. First, the pacing spike itself is subtracted. Next, the polarization atrifact is exponentially approximated using a second order linear predictor with a least squares estimator; this exponential is then subtracted. This allows the evoked response to be retained, even through it occurs in the middle of the exponential polarization atrifact.
Finally, pacing spikes due to pacemaker outputs on one channel are similarly removed from the other ICEG channel. In addition, the large "far field" polarization artifacts seen in the atrial channel due to ventricular outputs are exponentially removed.
The result of this sep is a set of ECG/ICEG signals with all pacing artifacts removed, but with all spontaneous and evoked cardiac activity retained. FIGS. 5A-5B illustrate this process. FIG. 5A shows a sampled ICEG (idealized) including a pacing spike and a repolarization atrifact. FIG. 5B shows the results of subtracting the pacing spike and the exponentially approximated repolarization atrifact. The remaining signal (shown as a sine wave) would represent the cardiac activity.
Detection Of Cardiac Activity
Cardiac activity (either spontaneous or evoked) is detected via a two-step process. First, a simple detector scans each signal channel for possible areas of activity. Next, a "smart" detector scans all three signals simultaneously, looking at each area identified by the simple detector.
The simple detector uses a level threshold to locate areas of possible cardiac activity. It independently scans each signal channel (surface ECG, atrial ICEG, and ventricular ICEG) to locate areas where the signal exceeds a defined threshold. The threshold is determined for each channel based on the mean, deviation, and peak values of the signal in that channel. The locations of these "candidate" areas are stored for use by the "smart" detector. (The primary purpose of this "simple" detector is to reduce the amount of signal the computationally intensive "smart" detector must process.)
The smart detector uses a set of "expectancy" matrices. These prestored matrices essentially contain what the device "expects" each type of event (atrial activity, ventricular activity, and noise) to look like across all three channels over a small sequence of samples. They were obtained by taking the mathematical inverse of "observed" signal matrices. The "observed" matrices were based on the combination of a large number of observations of each type of activity.
The "smart" detector scans each type of expectancy matrix across all three simultaneous signals for each area identified by the "simple" detector, determining a "detector output" for each point in the candidate area. It also determines the first and second moment of the detector output. Based on these results, it selects the most probable identification of each candidate area (atrial activity, ventricular activity, or noise) and identifies the fiducial point (or common time reference point) for each area identified as cardiac activity. FIG. 6 illustrates this process. The upper section shows three (stylized) simultaneous data signals--the surface ECG, the atrial ICEG, and the ventricular ICEG. Immediately below each signal are indicated the "Candidate" areas identified by independently scanning each signal with the simple detector. The lower section shows the output of each of the smart detectors over each identified candidate area. These are obtained by independently scanning each smart detector over all three data signals simultaneously. Note that the outputs of the smart detectors exist only for simple detector identified candidate areas. The bottom line indicates the decision made about each candidate area, based on the relative outputs of the smart detectors. Each candidate area is identified as either atrial activity, ventricular activity, or noise (no cardiac activity).
Correlation With Activity Indicators
This step examines each identified occurrence of cardiac activity and attempts to associate it with a previously identified pacemaker action (such as a sense or a pace). For example, cardiac activity on a particular channel immediately following a pacemaker output on that channel would be considered as an evoked response, and would be evidence that the pacemaker output had "captured" the chamber. Those occurrences of cardiac activity which cannot be associated with an appropriate pacemaker activity indicator are retained as separate events. An example of this would be an unsensed P wave.
Formatting the Event List
The last step in the digital signal processing unit is to sequentially sort the identified events, and to write them in a standard format into the "event list". It is this list of discrete events that will be analyzed by the paced ECG event analysis unit. FIG. 7 shows the (stylized) surface ECG and the activity indicators for that section of the data. FIG. 8 is an event list corresponding to the data section of FIG. 7.
PACED ECG EVENT ANALYSIS UNIT 24
The purpose of the paced ECG event analysis unit is to examine each individual event and determine if the pacemaker functioned properly. For example, did it sense (or not sense) spontaneous cardiac activity when it was supposed to, did it output a pacing pulse at the correct time, did the pacing pulse capture the heart (produce an evoked response in the paced chamber), did the refractory periods end on time, were there any occurrences of PVCs, PACs, or special pacemaker mediated events, etc.
As each event is analyzed, several status indicators are determined for each event. These include sensing status, pacing (timing) status, capture status, state change timing (such as end of refractory period) status, and special (PVC, anti-PMT dropped beat, ventricular safety pace beat, etc.) statuses. The possible values for each status indicator include all possible normal and abnormal functional conditions for that pacemaker function. For example, the possible values for sensing status include three normal conditions (OK) and five abnormal conditions (NG), as follows:
______________________________________                                    
STATUS          MEANING                                                   
______________________________________                                    
OK - Unobserved:                                                          
                No cardiac activity and no sense                          
                indicator,                                                
OK - Ignored:   Cardiac activity properly not                             
                sensed,                                                   
OK - Sensed:    Cardiac activity properly sensed,                         
NG - Undersense:                                                          
                Cardiac activity not sensed when                          
                it should have been,                                      
NG - Oversense: Sense indicator with no cardiac                           
                activity,                                                 
NG - Sense in Off:                                                        
                A sense indicator from a channel                          
                with sensing turned off,                                  
NG - Sense in   A sense indicator during the                              
Blanking:       blanking period of a channel,                             
NG - Indicated Sense                                                      
                Sense indicator during special                            
In Noise Window noise blanking period.                                    
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Since is is possible for several abnormal conditions to occur at the same time (for example, an oversense in the blanking period), the unit identifies the most serious problem, and assigns that status indicator value for the event.
The paced ECG event analysis unit is based on a detailed model of the functioning relationships incorporated in the pacemaker's hardware and software, expressed as a set of logical rules. These rules predict exactly what the pacemaker is expected to do in any situation, based on the programmed parameter values. The unit compares the expected functioning (as predicted by the model) with the observed functioning (as evidenced by the event list) to determine the status of each pacemaker function for each event.
The paced ECG event analysis unit performs a five step process, with the last four steps repeated sequentially for each entry in the event list, as follows:
1. Initialization,
2. "Missing" event detection,
3. Status indicator determination,
4. Update the model, and
5. Check for ("non-event") state change indicators. FIG. 9 shows the overall flow of information in this unit.
Initialization
In order to determine how the pacemaker should act at a given moment it is necessary to know the "state" of the pacemaker; i.e., the value of every variable in the pacemaker at that moment in time. For example, to determine if the pacemaker should sense a P-wave, it is necessary to know if atrial sensing is on or off, and, if it is on, is the channel blanked, refractory, alert, or in a noise window. The values of these internal pacemaker variables depend on both the programmed parameter values and the past experience (history) of the pacemaker. While all programmed parameter values are known, the history of the pacemaker is not known at the beginning of the ECG/ICEG data segment. Initialization establishes its state.
Initialization is accomplished by assuming that the pacemaker is functioning properly, and examining how it acted in response to the heart's actions early on in the data segment. For example, if a DDD pacemaker's first action was to pace the atrium, then it is assumed to have been in the atrial escape interval at the start of the data segment. Since both the number of possible pacemaker states and the number of first actions are finite (though large), an exhaustive analysis of the responses to initial actions allows the pacemaker's state at the start of the data to be uniquely determined. Once the initial state of the pacemaker has been determined, each subsequent event can then be sequentially analyzed. FIG. 10 shows the sequence of information flow for this unit.
Missing Event Detection
The analysis of each event begins by checking to see if any event should have occurred after the last analyzed event and prior to the specific event that is about to be analyzed; i.e., is any expected event "missing." This can occur for two reasons, pacemaker malfunction or unobserved pacemaker state changes. If a "missing event" is identified, it is inserted into the event list ahead of the event about to be analyzed. The inserted "missing" event will be analyzed next, before the event that was about to be analyzed. Examples of each type of "missing event" follow. FIG. 11 shows the decision structure for identifying "missing" events.
Suppose that a VOO pacemaker is programmed to 60 beats per minute, and that the interval from the previous event (a ventricular pace) to the event about to be analyzed in the event list is 1,200 milliseconds. Obviously, the pacemaker should have output a pulse 1,000 milliseconds after the previous event, and did not--it malfunctioned. This is accommodated by adding an event to the event list at 1,000 milliseconds after the previous event (200 milliseconds before the event that was about to be analyzed). When this "added" event is analyzed, it will indicate a failure to pace when expected.
However, "missing events" can also occur during normal pacemaker functioning. For example, consider a VDD pacemaker. Assume that following a ventricular pace, no atrial activity is detected for the entire minimum rate determined beat to beat interval. The pacemaker would then correctly pace the ventricle. However, the atrial escape interval has ended and the ventricular escape interval (or AV delay) has started with no activity indicator. To allow the model to correctly process this state change, an event would be added to the event list at the expected end of the atrial escape interval. (This is identified as a "phantom" event and is only used internally for analysis; it is not identified as an event to the user.)
Status Indicator Determination
Knowing the state of the pacemaker, it is possible to determine if it functional properly at each event. Each event is analyzed, based on the metrics determined by the digital signal processing unit. A single value is assigned to each status for every event.
Separate rules evaluate the various functions and determine the value of each status indicator for the event. A typical rule from the evaluation of capture status might read:
______________________________________                                    
IF          Pacing output is present and evoked                           
            response is present                                           
THEN        Capture status is "OK - captured"                             
______________________________________                                    
The rules used are based on a rigorous, exhaustive analysis of all possible combinations of relevant event metrics and pacemaker programmed parameter values, and were verified by clinical experts. The rules are independent of the channel where the event occurred, except for events such as premature ventricular contractions or retrograde P waves, which can occur only on a specific channel.
Update the Model
Each event may change the state of the pacemaker. This will affect the way in which it responds to the next event. This step in the paced ECG event analysis determines the way in which the state of the pacemaker has been changed by the event just analyzed. In essence, it "updates" the running model of the pacemaker, and prepares it to evaluate the next event. The following Chart B shows the input variables used by, and the possible outcomes for, each set of event status determination rules--sensing, pacing (timing) and capture. Note that the same rules apply to both the atrial and ventricular channels, and are applied independently to each.
______________________________________                                    
CHART B                                                                   
Status Indicator Determination                                            
______________________________________                                    
A. Sensing Status                                                         
Input Variables                                                           
Sense Amplifier State:                                                    
             Off, Blanked, Refractory, Alert,                             
             Noise Window/Possible,                                       
             Noise Window/Definite                                        
Spontaneous Cardiac Activity: Absent, Present                             
Sense Activity Indicator: Present, Absent                                 
Possible Outcomes                                                         
OK - Unobserved                                                           
OK - Ignored                                                              
OK - Sensed                                                               
NG - Undersense                                                           
NG - Oversense                                                            
NG - Sense When Off                                                       
NG - Sense in Blanking                                                    
NG - Sense in Noise Window                                                
B. Pacing (Timing) Status                                                 
Input Variables                                                           
Mode                                                                      
Pacing: Off, On                                                           
Sensing: Off, On                                                          
Triggering: Off, On                                                       
Event Time = End of Escape Interval (within allowed Minimum               
and Maximum Tolerance): No, Yes, Uncertain                                
Correct Sense (Sense when not Refractory and not in Ventricular           
Safety Pace Window): No, Yes                                              
Pace Activity Indicator: Absent, Present                                  
Possible Outcomes                                                         
OK - No Output Expected                                                   
OK - No Output Expected/Phantom                                           
OK - Output When Expected                                                 
OK - Output Timing Uncertain                                              
NG - No Output When Expected                                              
NG - Output When Not Expected                                             
NG - Output Triggering                                                    
NG - Output When Off                                                      
C. Capturing Status                                                       
Input Variables                                                           
Pace Activity Indicator: Absent, Present                                  
Pacing Output Pulse: Absent, Present                                      
Spontaneous Cardiac Activity: Absent, Present                             
Evoked Response: Absent, Present                                          
Possible Outcomes                                                         
OK - Unobserved, No Pacer Output                                          
OK - Unobserved, Competitive Pacing                                       
OK - Captured                                                             
NG - No Capture Observed                                                  
NG - No Capture, Output Pulse Missing                                     
______________________________________                                    
It is based on the detailed model of the pacemaker functional relationships and the programmed parameter values. However, the model has been expended to allow for uncertainties due to both real world timing tolerances and imprecise or incomplete history.
For example, the duration of the AV delay may be a function of whether or not the two previous atrial events were paced or sensed. If this is not shown (such as on the second beat), the model would be updated to show a range of allowable AV delays, based on however much history is known. When the next ventricular event is analyzed, AV delays falling anywhere in this range would be considered correct functioning. FIG. 12 shows the steps involved in updating the pacemaker model, depending on the type of event that has occurred. Note that the process is similar, regardless of the channel on which the event occurred.
Check For State Change Indicators
Certain state changes within the pacemaker are signaled by telemetered activity indicators, but are not considered as pacemaker/patient events. They were indicated in the event list by noting the time they occurred after the immediately preceding true event. The last step in the analysis of a single event is to look for any such indicators and verify their function and timing. The following Chart C shows the input variables and possible outcomes for a typical state change activity indicator status determination, the end of refractory period activity indicator. Note that the same rules apply to both the atrial and ventricular channels, and are applied independently to each.
______________________________________                                    
CHART C                                                                   
State Change Indicator Status                                             
End of Refractory (EOR) Activity Indicator Status                         
______________________________________                                    
Input Variables                                                           
Channel Refractory: No, Yes                                               
EOR Minimum Time After This Event, Before Next Event:                     
No, Yes                                                                   
EOR Nominal Time After This Event, Before Next Event:                     
No, Yes                                                                   
EOR Maximum Time After This Event, Before Next Event:                     
No, Yes                                                                   
EOR Activity Indicator: Absent, Present                                   
EOR Activity Indicator Time:                                              
                 Less Than EOR Minimum Time,                              
                 Between Minimum and Maximum.                             
                 Greater Than EOR MAximum                                 
                 Time                                                     
Possible Outcome                                                          
OK - No EOR Activity Indicator Expected                                   
OK - EOR Activity Indicator On Time                                       
NG - EOR Activity Indicator Early                                         
NG - EOR Activity Indiator Late                                           
NG - EOR Activity Indicator Missing                                       
NG - Extra EOR Activity Indicator                                         
______________________________________                                    
This completes the analysis of an event in the event list. The last four steps are repeated until the end of the event list is reached.
CLINICAL ANALYSIS AND ADVISOR UNIT 26
The purpose of the clinical analysis and advisor unit is to combine the results of the analyses of the individual events into a single comprehensive evaluation of the implanted cardiac pacemaker system.
Following the paced ECG event analysis, the event list contains the signal analysis metrics and statuses for each patient/pacemaker interaction or event. The clinical analysis and advisor unit uses expert system techniques to combine the information in the event list with patient and pacemaker data, and a knowledge base of clinical expertise in ECG problem solving to produce a summary analysis of the functional condition of the implanted pacemaker; including any identified problem(s), their probable cause(s), and clinically acceptable actions to correct them.
The clinical analysis and advisor unit uses a clinical knowledge base organized into a series of frame-like structures; that is, separate structures for problems relating to pacing leads, pacing rate, pacemaker electronic malfunctions, pacing and sensing thresholds, pacing lead configurations, etc. This allows the unit to search the knowledge base much as a clinician would analyze a paced ECG in actual practice.
This structuring also allows each step of the analysis to be individually examined and validated. Because each structure covers a limited and defined domain (set of possible inputs, problems, and causes) it can be rigorously validated, often by exhaustive search of all possible input combinations and their resulting outputs. This is typically not possible in most expert systems which do not employ such a frame-like structuring.
The clinical analysis and advisor unit uses a four step process, as follows:
1. Data reduction (and summarization),
2. Problem identification,
3. Determination of problem causes, and
4. Provision of clinical advice.
FIG. 13 shows the sequence of events in this unit.
In the present implementation, steps three and four of this process were combined into a single step. Therefore, in the following descriptions, the purposes of these last two steps will be separately described, and then their implementation as a single step will be described.
Data Reduction
To allow the clinical analysis and advisor unit to examine and sort out the large amount of information presented to it in any reasonable time, data reduction is necessary. This is accomplished in four separate areas; reduction of programmed parameter and stored patient information values, reduction of strings of events into the larger clinical P-QRS complexes called "beats," identification of clinically significant ECG patterns over multiple events, and summarizing of common event status values. These reductions are accomplished by the sequential application of a series of pre-stored rules or "Productions" in an "IF (FACTS) . . . THEN (ACTIONS) . . . " format, and random access memory search and update methods.
The number of programmable parameter values stored in the pacemaker can cause a combinatorial explosion, results in an unmanageable number of logic tests being needed to arrive at a single analysis result. These programmable parameter values are reduced to a manageable number by symbolic representations. For example, a pacemaker may have up to 128 possible combinations for pacemaker output amplitude and pulse width. This is first reduced by combining the two values into a single value representing the total charge delivered by the output. This might reduce the 128 values by more than half. Next these charge values are ordered and identified as falling into one of five clinically significant symbolically labelled categories. A set of 40 charge values might be labelled as follows:
______________________________________                                    
Minimum - Lowest (Value 1)                                                
Low - Next 9 (Values 2 through 10)                                        
Mid Range - Next 20 (Values 11 through 30)                                
High - Next 9 (Values 31 through 39)                                      
Maximum - Highest (Value 40)                                              
______________________________________                                    
A similar example is the reduction of the stored implant date and the present date into a single designation of whether the implant is "acute" or "chronic."
The second data reduction is performed primarily to reduce the amount of information that will have to be presented to the clinician. Separate events are combined into larger P-QRS complexes identified as "beats." This allows the conversion of references from the exact time domain into the clinical terms normally used in discussing ECGs. Thus, rather than reporting an atrial event which occurred at 2895 milliseconds into the data segment, the device can refer to the atrial part of P-QRS beat 3. This reduction is accomplished by a set of rules that examine the order and type of atrial and ventricular events within specific time limits.
Productions are also used to combine the order and timing of individual events to identify ECG occurrences that happen over several beats, such as retrograde P waves, premature ventricular contractions, or pacemaker mediated tachycardia. These identifications are added to the individual event descriptions in the Event List before summarization.
At the same time, questionable occurrences are examined and verified. For example, it is not always possible to directly verify atrial capture, since the atrial evoked response is not always clearly identifiable in the ECG or ICEG. Digital signal processing may fail to identify it, with the result theat atrial capture status is classified as "unknown." However, by examining a series of events, there may be "further evidence" indicating atrial capture. If there are instances where atrial paced events are consistently followed by spontaneous ventricular contractions within a normal AV delay range, then atrial capture can be assumed to have occurred, and the atrial capture status is changed to "OK--Captured."
Finally, the entire list of individual events and their separate status values are summarized to produce a single event status summary record. This summary contains, for each channel, the type of event (sensed, paced, etc.) and the common status values found in the different beats. It is this event status summary record, in combination with pacemaker and patient data, which is primarily used for problem identification. FIG. 14 shows the sequential flow of these activities. FIG. 15 shows the event status summary record that would be produced for the sample (stylized) surface ECG shown in FIG. 15B. The record is based on the analysis of all the signals, not just the surface ECG. The surface ECG is included here for illustrative purposes only.
Problem Identification
Once the event status summary record has been produced, it is scanned via a computed "key" access (based on the channel, the number of records, and status indicator) to the record, to determine the operational status of each of the pacemaker's functions (sensing, pacing, timing and capture) for each channel. The productions examine the status indicator values for each particular function for all events. Functions are identified as having one of four operational states, as follows:
Unobserved: The particular function was never observable during the ECG data segment. (Example: Atrial sensing when no P waves were present.)
Normal: The particular function was observable at least once during the ECG data segment; and its status was OK every time it was observed. (Example: Proper atrial sensing of intermittent P waves with no over-sensing when P waves not present.)
Abnormal-Intermittent: The particular function was observable at least twice during the ECG data segment; its status was OK at least once and No Good at least once. (Example: Multiple paced atrial beats, with the atrium captured on some beats and not on others.)
Abnormal--Complete (or Constant): The particular function was observable at least once during the ECG data segment; its status was No Good every time it was observed. (Example: One or more paced atrial beats, none of which captured the atrium.)
In addition, any special status indicators are reviewed for possible improper functioning.
Where any abnormal functioning is identified, the beats on which the function's status was No Good are noted. These will be reported to the clinician.
At this stage in its analysis, the device has simply "reviewed" the ECG and "reported" its findings, "flagging" any abnormalities. There has been no identification of the possible causes of any of the observed abnormalities, and no determination of future clinical actions, either diagnostic or therapeutic. In certain applications, this would be the appropriate termination of the analysis. In those cases, the remaining stages in the clinical analysis and advisor unit would be disabled, and the present coded analysis results would be directly passed to the results output unit.
FIG. 16 shows the sequential identification of problems with each of the different pacer functions.
Determination of Problem Causes
Once individual problems (or malfunctions) have been identified, the device must determine what caused the problem(s). Because of the complex interactions within the implanted system, multiple observed problems may in fact have a common cause. For example, a dislodged atrial lead could cause both intermittent atrial under sensing and complete loss of atrial capture; in the presence of retrograde conduction, this could also yield retrograde P waves. Alternately, consistent atrial undersensing along with complete loss of atrial capture could be due to an atrial lead problem (fracture, dislocation, etc.) or to separately programmed inappropriate values for atrial output and atrial sensitivity.
Problem causes are grouped by engineering system (pacemaker timing control, output circuits, sensing circuits, leads, etc.), with each system being sequentially examined. The stored knowledge base used to identify problem causes is based upon a structured representation of information derived primarily from pacemaker system engineers, and secondarily from experienced clinicians, obtained through both reviews of published material and extensive interviews.
Because specific system malfunctions may cause multiple observed problems, it is necessary to examine not only separate observed problems, but also combinations of problems. To assist in identifying problem causes, stored information (such as pacemaker measurements and stored patient information) as well as programmed parameter values are combined with the information on the observed problems. Where a single cause cannot be positively identified, multiple possible causes are retained.
Provision Of Clinical Advice
Once the causes of the observed pacemaker system problems have been identified, possible corrective actions can be identified. Determining the proper action to correct a specific problem is a clinical task, clearly requiring an experienced medical practitioner. The device's ability to recommend actions is severely constrained by both ethical and legal considerations. It is not within the scope of any device to practice clinical medicine. However, it is within the scope of this device to provide the clinician with a set of reminders, encompassing clinically accepted techniques for rectifying each identified problem, along with a list of "relevant" patient and/or pacemaker information.
Another knowledge base (obtained primarily from clinical experts) is used to identify appropriate and generally accepted clinical procedures. These may include both specific actions (such as reprogramming the pacemaker) and diagnostic procedures (such as fluoroscopic examination of the lead). The recommendations are based not only on the observed problem, but also on stored information about the pacemaker and the patient. For example, increasing the pacemaker's output would not be recommended if the pacemaker were already at maximum output, while reducing the pacing rate to attempt to observe atrial sensing would not be recommended if the patient has a pre-pacing history of syncope.
In addition to identifying possible actions, the device also identifies specific facts from the stored information which are relevant to the actions identified. These are passed to the results output unit along with the actions.
Joint Implementation--Determination Of Problem Causes and Provision Of Clinical Advice
In its present implementation, the two separate steps of determination of problem causes the provision of clinical advice have been combined into a single step. The two separate knowledge bases were combined into a common sets of productions with a single inference engine.
As in other units, the productions in this step use the "IF (FACTS) . . . THEN (ACTIONS) . . . " structure. FACTS are the combinations of symbolic representations of the stored pacemaker data, quantitative and symbolic paced ECG event metrics, and the summary of the statuses for each event. Each "FACTS" part of a production essentially represents a possible problem state. The "ACTION" part of a production contains relevant pacemaker programmed variables to be displayed, a statement of both normal and abnormal events and where they occur (P-QRS beats), the probable cause of the abnormal event, some reasoning about the event (if possible) and recommendations for actions to correct the problem.
An example of a production from this step is:
______________________________________                                    
IF    COMPLETE LOSS of (channel) SENSING and                              
      (channel)                                                           
      SENSITIVITY is MAXIMUM and COMPLETE LOSS                            
      of (channel) CAPTURE and (channel) OUTPUT                           
      is HIGH and (channel) IMPLANT-TIME is                               
      ACUTE                                                               
THEN                                                                      
Display:   (channel) SENSITIVITY value                                    
Display:   (channel) OUTPUT value                                         
Display:   "Examine (channel) lead for possible                           
           repositioning."                                                
Display:   "Watch for Diaphragmatic Stimulation                           
           due to the HIGH OUTPUT value."                                 
______________________________________                                    
The productions are grouped (framed) into problem categories. That is: pacemaker malfunctioning, pacing leads, pacing and sensing thresholds, pacing rate, etc.
The mechanism to search through the entire knowledge base of productions is called an "inference engine." Each production is examined, and if the "FACTS" part is true, then the production is instantiated and the "ACTIONS" occur. If false, then the search continues to process the other productions. The order of the search through the productions emulates the way in which a clinician would view and analyze a patient's paced ECG. FIG. 17 shows the structure of the Expert System that is used for the joint implementation of these two steps, indicating the types of information stored in each section of the data base.
RESULTS OUTPUT UNIT 28
The purpose of the results output unit is to present the conclusions from the analyses to the clinician. Depending on the capabilities of the output unit, results may be presented either as a single entity or as a sequential series of presentations, either on a visual display or in "hard copy."
Regardless of the output mechanism used, the results output unit performs several functions. First, it combines the stored surface ECG with the derived beat identifications and stored activity indicators to provide an annotated ECG. Second, it provides a display of the summarized results for each channel, identifying all observed and unobserved functional status for each channel, with all abnormal findings clearly labelled. Finally, for every abnormal finding, it lists the relevant pacemaker and patient data, the probable causes, and possible corrective actions.
This unit includes large scale editing and code conversion sections, to convert the internal coded information into specific user readable outputs, tailored to the specific display being used, as well as the connectors and drivers for the actual output unit employed.
Although an illustrative embodiment of the invention has been shown and described, it is to be understood that various modifications and substitutions may be made by those skilled in the art without departing from the novel spirit and scope of the present invention.

Claims (16)

What is claimed is:
1. A cardiac pacer analysis system, which comprises:
means for receiving and storing information telemetrically transmitted from an implanted pacer;
means for identifying and characterizing events in the received information;
means for identifying observed problems that are based on the events and on logical rules which express the functioning relationships incorporated in the operation of the implanted pacer;
means for automatically determining probable causes of observed problems and possible corrective actions; and
means for displaying the results of the automatic determinations to a clinician by including selected clinically relevant information.
2. A system as described in claim 1, in which the information received includes pacer parameter programmed values, pacer stored patient-related information, results of automatically performed pacer measurements, and a surface ECG signal presented as an analog signal.
3. A cardiac pacer analysis system as described in claim 1, including means for automatically providing a sampling segment, checking the sampling segment to determine if it is satisfactory for reference purpose, identifying proper pacing spikes and removing the improper spikes, detecting the cardiac activity, and correlating the detected cardiac activity with previously received information.
4. A cardiac pacer analysis system as described in claim 1, including means for automatically comparing observed events with model information that is previously stored in the analysis system, including means for automatically determining the initial state of the pacer, checking for missing events, determining if the pacer is functioning properly at each of the observed events, updating the stored model information to prepare for evaluating the next event, checking for state changes within the pacer, and providing an event list based on said comparison.
5. A cardiac pacer analysis system as described in claim 4, including means for automatically reducing the amount of received data, summarizing the events to produce a summary record, identifying the operational status of each of the pacer's functions for each channel, noting any abnormal function, comparing abnormal functioning data with previously stored information to determine problem causes, and displaying recommended corrective action.
6. A cardiac pacer analysis system which comprises:
a signal receiving and storage means for accepting surface ECG and telemetrically transmitted information from the pacer and storing said information;
a digital signal processing means responsive for the signal receiving and storing means for identifying and characterizing the received ECG data;
an ECG event analysis means responsive to the digital signal processing means for automatically determining if the pacer functioned correctly and produced the clinically desired response from the patient at each ECG event;
a clinical analysis and advisor means responsive to the ECG event analysis means for automatically summarizing the results and identifying any observed problems and automatically providing probable causes and possible actions that a physician can take to alleviate the observed problem; and
a results output means for automatically presenting results of the ECG event analysis and the clinical event analysis by including selected relevant clinical information to a clinician.
7. A cardiac pacer analysis system for use with a cardiac pacer in which patient history information is stored within the pacer, which comprises:
storage means containing a knowledge base encompassing the functional characteristics of the pacer;
means for automatically receiving information including surface ECG information and telemetered ICEGs from the pacer;
means for automatically sorting by time and type of signal the received information signals and providing a sampling segment;
means for automatically examining each sampling segment to determine if the pacer functions properly; and
means for automatically analyzing the received information to provide a comprehensive assessment of the implanted pacer.
8. A system as described in claiim 7, in which the information received includes pacer parameter programmed values, pacer stored patient-related information, results of automatically performed pacer measurements, and a surface ECG signal presented as an analog signal.
9. A cardiac pacer analysis system as described in claim 7, including means for automatically checking the sampling segment to determine if it is satisfactory for reference purpose, detecting the cardiac activity, and correlating the detected cardiac activity with previously received information.
10. A cardiac pacer analysis system as described in claim 7, including means for automatically comparing observed events with previously stored model information, including means for automatically determining the initial state of the pacer, checking for missing events, determining if the pacer is functioning properly at each of the observed events, updating the stored model information to prepare for evaluating the next event, checking for state changes within the pacer, and providing an event list based on said comparison.
11. A cardiac pacer analysis system as described in claim 10, including means for reducing the amount of received data, summarizing the events to produce a summary record, identifying the operational status of each of the pacer's functions for each channel, noting any abnormal function, comparing abnormal functioning data with previously stored information to determine problem causes, and displaying recommended corrective action.
12. A cardiac pacer analysis system as described in claim 7, in which the pacer stored patient-related information includes the implant date, lead type and location, and pre-implant symptoms.
13. A cardiac pacer analysis system as described in claim 7, in which the pacer's functions include sensing pacing timing and capture for each channel.
14. A cardiac pacer analysis system which comprises:
means for receiving and storing telemetrically transmitted information, including pacer parameter programmed values, pacer stored patient-related information, results of automatically performed pacer measurements, and a surface ECG signal presented as an analog signal;
means for automatically sorting the signals and producing a sampling segment;
means for automatically detecting cardiac activity and correlating the detected cardiac activity with a previously identified pacer action;
means for automatically sorting the identified events;
means for automatically examining each event and determining if the pacer functions properly; and
means for automatically providing a comprehensive evaluation of the implanted pacer.
15. A cardiac pacer analysis system as described in claim 14, in which the providing means includes means for automatically reducing the amount of received data, summarizing the events to produce a summary record, identifying the operational status of each of the pacer's functions for each channel, noting any abnormal functioning, comparing abnormal functioning data with previously stored information to determine problem causes, and displaying recommended corrective action.
16. A cardiac pacer analysis system as described in claim 14, including means for automatically comparing observed events with previously stored model information, said comparing means including means for automatically determining the initial state of the pacer, checking for missing events, determining if the pacer is functioning properly at the observed event, updating the stored model information to prepare for evaluating the next event, and checking for state changes within the pacer.
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Cited By (130)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5027814A (en) * 1989-05-19 1991-07-02 Ventritex, Inc. Implantable medical device employing an improved waveform digitization network
US5042497A (en) * 1990-01-30 1991-08-27 Cardiac Pacemakers, Inc. Arrhythmia prediction and prevention for implanted devices
US5226086A (en) * 1990-05-18 1993-07-06 Minnesota Mining And Manufacturing Company Method, apparatus, system and interface unit for programming a hearing aid
US5240009A (en) * 1991-03-25 1993-08-31 Ventritex, Inc. Medical device with morphology discrimination
US5292341A (en) * 1992-03-02 1994-03-08 Siemens Pacesetter, Inc. Method and system for determining and automatically adjusting the sensor parameters of a rate-responsive pacemaker
US5404877A (en) * 1993-06-04 1995-04-11 Telectronics Pacing Systems, Inc. Leadless implantable sensor assembly and a cardiac emergency warning alarm
EP0669841A1 (en) * 1993-08-27 1995-09-06 Siemens Pacesetter, Inc. Programming system for a patient's cardiac signal
US5507786A (en) * 1994-04-14 1996-04-16 Pacesetter, Inc. System and method for measuring and storing parametric data pertaining to operating characteristics of an implantable medical device
US5518001A (en) * 1994-06-17 1996-05-21 Pacesetter, Inc. Cardiac device with patient-triggered storage of physiological sensor data
US5540232A (en) * 1992-11-16 1996-07-30 Del Mar Avionics Method and apparatus for displaying pacer signals on an electrocardiograph
US5594638A (en) * 1993-12-29 1997-01-14 First Opinion Corporation Computerized medical diagnostic system including re-enter function and sensitivity factors
EP0756877A2 (en) * 1995-08-02 1997-02-05 Pacesetter, Inc. Decision support system and method for an implantable cardiac stimulating device
US5605158A (en) * 1995-08-02 1997-02-25 Pacesetter, Inc. Apparatus for annotating physiological waveforms
US5607460A (en) * 1996-03-15 1997-03-04 Angeion Corporation Physician interface expert system for programming implantable arrythmia treatment devices
US5660183A (en) * 1995-08-16 1997-08-26 Telectronics Pacing Systems, Inc. Interactive probability based expert system for diagnosis of pacemaker related cardiac problems
US5660176A (en) * 1993-12-29 1997-08-26 First Opinion Corporation Computerized medical diagnostic and treatment advice system
US5711297A (en) * 1993-12-29 1998-01-27 First Opinion Corporation Computerized medical advice system and method including meta function
US5713938A (en) * 1996-11-12 1998-02-03 Pacesetter, Inc. Fuzzy logic expert system for an implantable cardiac device
US5720771A (en) * 1995-08-02 1998-02-24 Pacesetter, Inc. Method and apparatus for monitoring physiological data from an implantable medical device
US5758095A (en) * 1995-02-24 1998-05-26 Albaum; David Interactive medication ordering system
US5782876A (en) * 1996-04-15 1998-07-21 Medtronic, Inc. Method and apparatus using windows and an index value for identifying cardic arrhythmias
EP0773038A3 (en) * 1995-11-07 1998-09-23 Telectronics N.V. Improved graphic interface for pacemaker programmers
US5891178A (en) * 1996-05-14 1999-04-06 Pacesetter, Inc. Programmer system and associated methods for rapidly evaluating and programming an implanted cardiac device
US5948005A (en) * 1997-01-28 1999-09-07 Pacesetter, Inc. Multi-event bin heart rate histogram for use with and implantable pacemaker
US5954666A (en) * 1995-08-04 1999-09-21 Pacesetter, Inc. System for analyzing specific portions of cardiac waveforms
US6016442A (en) * 1998-03-25 2000-01-18 Cardiac Pacemakers, Inc. System for displaying cardiac arrhythmia data
US6021351A (en) * 1998-05-11 2000-02-01 Cardiac Pacemakers, Inc. Method and apparatus for assessing patient well-being
US6206829B1 (en) 1996-07-12 2001-03-27 First Opinion Corporation Computerized medical diagnostic and treatment advice system including network access
US6259950B1 (en) 1996-05-14 2001-07-10 Pacesetter, Inc. Implantable stimulation device and method for determining a trial autocapture using backup atrial stimulation
US6263244B1 (en) 1996-05-14 2001-07-17 Pacesetter, Inc. Implantable stimulation device and method for determining atrial autocapture using PVC response
US6270456B1 (en) 1993-12-29 2001-08-07 First Opinion Corporation Computerized medical diagnostic system utilizing list-based processing
US6289244B1 (en) * 1999-08-20 2001-09-11 Cardiac Pacemakers, Inc. Self audit system
US6304778B1 (en) 1999-08-20 2001-10-16 Cardiac Pacemakers, Inc. Implantable defibrillators with programmable cross-chamber blanking
US6317633B1 (en) 1999-01-19 2001-11-13 Medtronic, Inc. Implantable lead functional status monitor and method
WO2002018009A1 (en) 2000-08-26 2002-03-07 Medtronic, Inc. Implantable lead functional status monitor and method
US6405087B1 (en) 2000-02-25 2002-06-11 Pacesetter, Inc. Cardiac stimulation system providing implantable device performance evaluation and method
US20020151809A1 (en) * 1999-08-20 2002-10-17 Cardiac Pacemakers, Inc. Method and system for identifying and displaying groups of cardiac arrhythmic episodes
US20020156389A1 (en) * 2001-02-28 2002-10-24 Cardiac Pacemakers, Inc. Cardiac rhythm management patient report
US20030060849A1 (en) * 1999-07-14 2003-03-27 Cardiac Pacemakers, Inc. Classification of supraventricular and ventricular cardiac rhythms using cross channel timing algorithm
US20030074036A1 (en) * 1998-02-06 2003-04-17 Intermedics Inc. Implantable device with digital waveform telemetry
US20030088290A1 (en) * 2001-11-07 2003-05-08 Spinelli Julio C. Centralized management system for programmable medical devices
US20030114891A1 (en) * 1999-08-22 2003-06-19 Cardiac Pacemakers, Inc. Event marker alignment by inclusion of event marker transmission latency in the real-time data stream
US6594523B1 (en) * 1996-05-14 2003-07-15 Pacesetter, Inc. Implantable stimulation device, programmer, and method for automatically evaluating interaction of the device with a patient's heart
US20030171791A1 (en) * 2002-03-06 2003-09-11 Kenknight Bruce H. Method and apparatus for establishing context among events and optimizing implanted medical device performance
WO2003077822A2 (en) 2001-12-31 2003-09-25 Medtronic,Inc. Imd lead status monitor method and system
US20030208240A1 (en) * 2002-05-03 2003-11-06 Pastore Joseph M. Method and apparatus for detecting acoustic oscillations in cardiac rhythm
US6650944B2 (en) 2000-02-23 2003-11-18 Medtronic, Inc. Follow-up monitoring method and system for implantable medical devices
US6665558B2 (en) 2000-12-15 2003-12-16 Cardiac Pacemakers, Inc. System and method for correlation of patient health information and implant device data
US6668188B2 (en) 2001-04-25 2003-12-23 Cardiac Pacemakers, Inc. Determination of long-term condition of cardiac patients
US20040010200A1 (en) * 2002-07-15 2004-01-15 Sweeney Robert J. Use of curvature based features for beat detection
US6684221B1 (en) * 1999-05-06 2004-01-27 Oracle International Corporation Uniform hierarchical information classification and mapping system
US20040064161A1 (en) * 2002-09-30 2004-04-01 Gunderson Bruce D. Method and apparatus for identifying lead-related conditions using lead impedance measurements
US6718198B2 (en) 1999-08-24 2004-04-06 Cardiac Pacemakers, Inc. Arrhythmia display
US20040093035A1 (en) * 2002-11-08 2004-05-13 Mark Schwartz Cardiac rhythm management systems and methods using multiple morphology templates for discriminating between rhythms
US20040111131A1 (en) * 2002-12-05 2004-06-10 Bo Hu Cardiac rhythm management systems and methods for rule-illustrative parameter entry
US20040122294A1 (en) * 2002-12-18 2004-06-24 John Hatlestad Advanced patient management with environmental data
US20040122485A1 (en) * 2002-12-18 2004-06-24 Stahmann Jeffrey E. Advanced patient management for reporting multiple health-related parameters
US20040122486A1 (en) * 2002-12-18 2004-06-24 Stahmann Jeffrey E. Advanced patient management for acquiring, trending and displaying health-related parameters
US20040122297A1 (en) * 2002-12-18 2004-06-24 Stahmann Jeffrey E. Advanced patient management for identifying, displaying and assisting with correlating health-related data
US20040122484A1 (en) * 2002-12-18 2004-06-24 John Hatlestad Advanced patient management for defining, identifying and using predetermined health-related events
US20040122295A1 (en) * 2002-12-18 2004-06-24 John Hatlestad Advanced patient management for triaging health-related data using color codes
US20040122487A1 (en) * 2002-12-18 2004-06-24 John Hatlestad Advanced patient management with composite parameter indices
US20040127792A1 (en) * 2002-12-30 2004-07-01 Siejko Krzysztof Z. Method and apparatus for monitoring of diastolic hemodynamics
US20040127806A1 (en) * 2000-10-31 2004-07-01 Cardiac Pacemakers, Inc. Curvature based method for selecting features from an electrophysiologic signals for purpose of complex identification and classification
US20040127950A1 (en) * 2002-12-31 2004-07-01 Jaeho Kim Capture verification using an evoked response reference
US20040127949A1 (en) * 2002-12-31 2004-07-01 Jaeho Kim Method and system for detecting capture with cancellation of pacing artifact
US20040143304A1 (en) * 2003-01-21 2004-07-22 Hall Jeffrey A. Recordable macros for pacemaker follow-up
US20040219600A1 (en) * 2002-12-13 2004-11-04 Williams Robert Wood Method for determining sensitivity to environmental toxins and susceptibility to parkinson's disease
US20040230456A1 (en) * 2003-05-14 2004-11-18 Lozier Luke R. System for identifying candidates for ICD implantation
US20040252078A1 (en) * 2003-06-13 2004-12-16 Fischer Jonathan H. Bi-directional interface for low data rate application
US20050033385A1 (en) * 2003-05-07 2005-02-10 Peterson Les Norman Implantable medical device programming apparatus having a graphical user interface
US20050137636A1 (en) * 2003-12-04 2005-06-23 Gunderson Bruce D. Method and apparatus for identifying lead-related conditions using impedance trends and oversensing criteria
US20050137627A1 (en) * 2003-12-22 2005-06-23 Koshiol Allan T. Synchronizing continuous signals and discrete events for an implantable medical device
US20050187588A1 (en) * 2000-12-15 2005-08-25 Cardiac Pacemakers, Inc. System and method for displaying cardiac events
US6980850B1 (en) * 2002-12-30 2005-12-27 Pacesetter, Inc. System and method for emulating a surface EKG using an implantable cardiac stimulation device
US6993379B1 (en) 2002-12-30 2006-01-31 Pacesetter, Inc. System and method for emulating a surface EKG using an implantable cardiac stimulation device
US20060025830A1 (en) * 2004-07-30 2006-02-02 Scott Freeberg Wireless pacing systems analyzer in a programmer system
US7010349B2 (en) 1999-08-20 2006-03-07 Cardiac Pacemakers, Inc. System and method for detecting and displaying parameter interactions
US20060058850A1 (en) * 2003-10-07 2006-03-16 Kramer Karen M Method and apparatus for managing data from multiple sensing channels
US20060111643A1 (en) * 2004-11-23 2006-05-25 Shelley Cazares Arrhythmia memory for tachyarrhythmia discrimination
US20060135855A1 (en) * 2002-12-20 2006-06-22 Koninklijke Philips Electronics N.V. Method for determining normal measurements for a patient
US20060211949A1 (en) * 2001-06-05 2006-09-21 Cardiac Pacemakers, Inc. System and method for classifying cardiac depolarization complexes with multi-dimensional correlation
US20060247706A1 (en) * 2005-04-29 2006-11-02 Germanson Nancy M Method and apparatus for dynamically monitoring, detecting and diagnosing lead conditions
US7181285B2 (en) 2000-12-26 2007-02-20 Cardiac Pacemakers, Inc. Expert system and method
US20070135851A1 (en) * 2000-08-29 2007-06-14 Cardiac Pacemakers, Inc. Implantable pulse generator and method having adjustable signal blanking
US20070203419A1 (en) * 2003-06-27 2007-08-30 Caridac Pacemakers, Inc. Tachyarrhythmia detection and discrimination based on curvature parameters
US20080021287A1 (en) * 2006-06-26 2008-01-24 Woellenstein Matthias D System and method for adaptively adjusting patient data collection in an automated patient management environment
US20080045811A1 (en) * 1997-03-13 2008-02-21 Clinical Decision Support, Llc Disease management system and method including significant symptom filtering
US20080103552A1 (en) * 2006-10-31 2008-05-01 Medtronic, Inc. Controller for obtaining prescriptive analysis of functionality of implantable medical device leads, system and method therefore
US20080103744A1 (en) * 2006-10-25 2008-05-01 Ai Medical Semiconductor Heart Simulator
US7500955B2 (en) 2003-06-27 2009-03-10 Cardiac Pacemaker, Inc. Signal compression based on curvature parameters
US20090248104A1 (en) * 2000-12-15 2009-10-01 Jiang Ding Automatic selection of stimulation chamber for ventricular resynchronization therapy
US20090259216A1 (en) * 2008-04-10 2009-10-15 Medtronic, Inc. Automated integrity tests
US20090299432A1 (en) * 2008-06-02 2009-12-03 Metronic, Inc. Impedance variability analysis to identify lead-related conditions
US20090299421A1 (en) * 2008-06-02 2009-12-03 Medtronic, Inc. Evaluation of implantable medical device sensing integrity based on evoked signals
US20090299429A1 (en) * 2008-06-02 2009-12-03 Medtronic, Inc. Sensing integrity determination based on cardiovascular pressure
US20090299422A1 (en) * 2008-06-02 2009-12-03 Medtronic, Inc. Electrogram storage for suspected non-physiological episodes
US20090299201A1 (en) * 2008-06-02 2009-12-03 Medtronic, Inc. Electrode lead integrity reports
US20090326600A1 (en) * 2008-06-30 2009-12-31 Medtronic, Inc. Lead integrity testing during suspected tachyarrhythmias
US20100016996A1 (en) * 2006-04-27 2010-01-21 Jeff West Medical device user interface automatically resolving interaction between programmable parameters
US20100030289A1 (en) * 2008-07-31 2010-02-04 Medtronic, Inc. Pre-qualification of an alternate sensing configuration
US20100106209A1 (en) * 2008-10-29 2010-04-29 Medtronic, Inc. Identification and remediation of oversensed cardiac events using far-field electrograms
US20100191544A1 (en) * 2009-01-27 2010-07-29 Adam Bosworth Protocol Authoring for a Health Coaching Service
US7780595B2 (en) 2003-05-15 2010-08-24 Clinical Decision Support, Llc Panel diagnostic method and system
US20100280838A1 (en) * 2009-05-01 2010-11-04 Adam Bosworth Coaching Engine for a Health Coaching Service
US20110184481A1 (en) * 2010-01-28 2011-07-28 Medtronic, Inc. Storage of data for evaluation of lead integrity
US8019582B2 (en) 2000-02-14 2011-09-13 Clinical Decision Support, Llc Automated diagnostic system and method
US8046060B2 (en) 2005-11-14 2011-10-25 Cardiac Pacemakers, Inc. Differentiating arrhythmic events having different origins
US8108034B2 (en) 2005-11-28 2012-01-31 Cardiac Pacemakers, Inc. Systems and methods for valvular regurgitation detection
USRE43433E1 (en) 1993-12-29 2012-05-29 Clinical Decision Support, Llc Computerized medical diagnostic and treatment advice system
US8260407B1 (en) 2005-09-12 2012-09-04 Pacesetter, Inc. Intracardiac device and method for storing cardiac test results and associated EGM data
US8437840B2 (en) 2011-09-26 2013-05-07 Medtronic, Inc. Episode classifier algorithm
US8521281B2 (en) 2011-10-14 2013-08-27 Medtronic, Inc. Electrogram classification algorithm
US8548576B2 (en) 2000-12-15 2013-10-01 Cardiac Pacemakers, Inc. System and method for correlation of patient health information and implant device data
US8600504B2 (en) 2010-07-02 2013-12-03 Cardiac Pacemakers, Inc. Physiologic demand driven pacing
US8744560B2 (en) 2011-09-30 2014-06-03 Medtronic, Inc. Electrogram summary
US8774909B2 (en) 2011-09-26 2014-07-08 Medtronic, Inc. Episode classifier algorithm
US8886296B2 (en) 2011-10-14 2014-11-11 Medtronic, Inc. T-wave oversensing
US8936555B2 (en) 2009-10-08 2015-01-20 The Regents Of The University Of Michigan Real time clinical decision support system having linked references
US9081879B2 (en) 2004-10-22 2015-07-14 Clinical Decision Support, Llc Matrix interface for medical diagnostic and treatment advice system and method
WO2015123483A1 (en) 2014-02-13 2015-08-20 Medtronic, Inc. Lead monitoring frequency based on lead and patient characteristics
US9211096B2 (en) 2009-10-08 2015-12-15 The Regents Of The University Of Michigan Real time clinical decision support system having medical systems as display elements
US9302100B2 (en) 2014-02-13 2016-04-05 Medtronic, Inc. Lead monitoring frequency based on lead and patient characteristics
US9378335B2 (en) 2009-11-23 2016-06-28 Keas, Inc. Risk factor engine that determines a user health score using a food consumption trend, and predicted user weights
US9399141B2 (en) 2014-02-13 2016-07-26 Medtronic, Inc. Lead monitoring frequency based on lead and patient characteristics
US9409026B2 (en) 2014-02-13 2016-08-09 Medtronic, Inc. Lead monitoring frequency based on lead and patient characteristics
US9522277B2 (en) 2008-07-28 2016-12-20 Medtronic, Inc. Lead integrity testing triggered by sensed signal saturation
US9668668B2 (en) 2011-09-30 2017-06-06 Medtronic, Inc. Electrogram summary
US9839784B2 (en) 2012-05-08 2017-12-12 Medtronic, Inc. Identifying lead insulation breaches and externalization of lead conductors
US10118042B2 (en) 2008-10-31 2018-11-06 Medtronic, Inc. Lead integrity testing triggered by sensed asystole

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4223678A (en) * 1978-05-03 1980-09-23 Mieczyslaw Mirowski Arrhythmia recorder for use with an implantable defibrillator
US4550370A (en) * 1982-10-29 1985-10-29 Medtronic, Inc. Pacemaker programmer with telemetric functions
US4596255A (en) * 1982-11-08 1986-06-24 Snell Jeffery D Apparatus for interpreting and displaying cardiac events of a heart connected to a cardiac pacing means
US4705042A (en) * 1985-05-21 1987-11-10 Cordis Corporation Pacing system analyzer having provision for direct connection of pacer to pacing leads

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4223678A (en) * 1978-05-03 1980-09-23 Mieczyslaw Mirowski Arrhythmia recorder for use with an implantable defibrillator
US4550370A (en) * 1982-10-29 1985-10-29 Medtronic, Inc. Pacemaker programmer with telemetric functions
US4596255A (en) * 1982-11-08 1986-06-24 Snell Jeffery D Apparatus for interpreting and displaying cardiac events of a heart connected to a cardiac pacing means
US4705042A (en) * 1985-05-21 1987-11-10 Cordis Corporation Pacing system analyzer having provision for direct connection of pacer to pacing leads

Non-Patent Citations (12)

* Cited by examiner, † Cited by third party
Title
Bernstein, et al., "Notation System and Overlay Diagrams for the Analysis of Paced Electrocardiograms", PACE, vol. 6, pp. 73-80 (Jan.-Feb. 1983).
Bernstein, et al., Notation System and Overlay Diagrams for the Analysis of Paced Electrocardiograms , PACE, vol. 6, pp. 73 80 (Jan. Feb. 1983). *
Dassen, et al., "Evaluation of Pacemaker Performance Using Computer Simulation" PACE, vol. 8, pp. 795-805 (Nov.-Dec. 1985).
Dassen, et al., Evaluation of Pacemaker Performance Using Computer Simulation PACE, vol. 8, pp. 795 805 (Nov. Dec. 1985). *
Manoli, et al., "An Algorithm for Arrhythmia Detection from Epicardial ECG", 37th ACEMB, p. 82 (Sep. 17-19, 1984).
Manoli, et al., An Algorithm for Arrhythmia Detection from Epicardial ECG , 37th ACEMB, p. 82 (Sep. 17 19, 1984). *
Olson, et al., "Pacemaker Diagnostic Diagrams" PACE, vol. 8, pp. 691-700 (Sep.-Oct. 1985).
Olson, et al., Pacemaker Diagnostic Diagrams PACE, vol. 8, pp. 691 700 (Sep. Oct. 1985). *
Sutton, et al., "Interpretation of Dual Chamber Pacemaker Electrocardiograms", PACE, vol. 8, pp. 6-16 (Jan.-Feb. 1985).
Sutton, et al., Interpretation of Dual Chamber Pacemaker Electrocardiograms , PACE, vol. 8, pp. 6 16 (Jan. Feb. 1985). *
Yeh, "Electrogram Evaluation By The Pacemaker Follow-Up Station", Cleveland Clinic Foundation (May 9, 1985).
Yeh, Electrogram Evaluation By The Pacemaker Follow Up Station , Cleveland Clinic Foundation (May 9, 1985). *

Cited By (293)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5027814A (en) * 1989-05-19 1991-07-02 Ventritex, Inc. Implantable medical device employing an improved waveform digitization network
US5042497A (en) * 1990-01-30 1991-08-27 Cardiac Pacemakers, Inc. Arrhythmia prediction and prevention for implanted devices
US5226086A (en) * 1990-05-18 1993-07-06 Minnesota Mining And Manufacturing Company Method, apparatus, system and interface unit for programming a hearing aid
US5240009A (en) * 1991-03-25 1993-08-31 Ventritex, Inc. Medical device with morphology discrimination
US5292341A (en) * 1992-03-02 1994-03-08 Siemens Pacesetter, Inc. Method and system for determining and automatically adjusting the sensor parameters of a rate-responsive pacemaker
US5540232A (en) * 1992-11-16 1996-07-30 Del Mar Avionics Method and apparatus for displaying pacer signals on an electrocardiograph
US5404877A (en) * 1993-06-04 1995-04-11 Telectronics Pacing Systems, Inc. Leadless implantable sensor assembly and a cardiac emergency warning alarm
EP0669841A1 (en) * 1993-08-27 1995-09-06 Siemens Pacesetter, Inc. Programming system for a patient's cardiac signal
EP0669841A4 (en) * 1993-08-27 1995-12-06 Siemens Pacesetter Programming system for a patient's cardiac signal.
US5724968A (en) * 1993-12-29 1998-03-10 First Opinion Corporation Computerized medical diagnostic system including meta function
USRE43433E1 (en) 1993-12-29 2012-05-29 Clinical Decision Support, Llc Computerized medical diagnostic and treatment advice system
US5594638A (en) * 1993-12-29 1997-01-14 First Opinion Corporation Computerized medical diagnostic system including re-enter function and sensitivity factors
US8015138B2 (en) 1993-12-29 2011-09-06 Clinical Decision Support, Llc Computerized medical self-diagnostic and treatment advice system
US6641532B2 (en) 1993-12-29 2003-11-04 First Opinion Corporation Computerized medical diagnostic system utilizing list-based processing
US6270456B1 (en) 1993-12-29 2001-08-07 First Opinion Corporation Computerized medical diagnostic system utilizing list-based processing
US7306560B2 (en) 1993-12-29 2007-12-11 Clinical Decision Support, Llc Computerized medical diagnostic and treatment advice system including network access
US5660176A (en) * 1993-12-29 1997-08-26 First Opinion Corporation Computerized medical diagnostic and treatment advice system
US5711297A (en) * 1993-12-29 1998-01-27 First Opinion Corporation Computerized medical advice system and method including meta function
US20050165285A1 (en) * 1993-12-29 2005-07-28 Iliff Edwin C. Computerized medical diagnostic and treatment advice system including network access
US7300402B2 (en) 1993-12-29 2007-11-27 Clinical Decision Support, Llc Computerized medical diagnostic and treatment advice system
US20030163299A1 (en) * 1993-12-29 2003-08-28 Iliff Edwin C. Computerized medical diagnostic and treatment advice system
US7297111B2 (en) 1993-12-29 2007-11-20 Clinical Decision Support, Llc Computerized medical diagnostic and treatment advice system
US6113540A (en) * 1993-12-29 2000-09-05 First Opinion Corporation Computerized medical diagnostic and treatment advice system
USRE43548E1 (en) 1993-12-29 2012-07-24 Clinical Decision Support, Llc Computerized medical diagnostic and treatment advice system
US9005119B2 (en) 1993-12-29 2015-04-14 Clinical Decision Support, Llc Computerized medical diagnostic and treatment advice system including network access
US5868669A (en) * 1993-12-29 1999-02-09 First Opinion Corporation Computerized medical diagnostic and treatment advice system
US20050154616A1 (en) * 1993-12-29 2005-07-14 Iliff Edwin C. Computerized medical diagnostic and treatment advice system
US8337409B2 (en) 1993-12-29 2012-12-25 Clinical Decision Support Llc Computerized medical diagnostic system utilizing list-based processing
US5507786A (en) * 1994-04-14 1996-04-16 Pacesetter, Inc. System and method for measuring and storing parametric data pertaining to operating characteristics of an implantable medical device
US5518001A (en) * 1994-06-17 1996-05-21 Pacesetter, Inc. Cardiac device with patient-triggered storage of physiological sensor data
US5758095A (en) * 1995-02-24 1998-05-26 Albaum; David Interactive medication ordering system
EP0756877A3 (en) * 1995-08-02 1998-06-03 Pacesetter, Inc. Decision support system and method for an implantable cardiac stimulating device
US5720771A (en) * 1995-08-02 1998-02-24 Pacesetter, Inc. Method and apparatus for monitoring physiological data from an implantable medical device
US5605158A (en) * 1995-08-02 1997-02-25 Pacesetter, Inc. Apparatus for annotating physiological waveforms
EP0756877A2 (en) * 1995-08-02 1997-02-05 Pacesetter, Inc. Decision support system and method for an implantable cardiac stimulating device
US5954666A (en) * 1995-08-04 1999-09-21 Pacesetter, Inc. System for analyzing specific portions of cardiac waveforms
US5660183A (en) * 1995-08-16 1997-08-26 Telectronics Pacing Systems, Inc. Interactive probability based expert system for diagnosis of pacemaker related cardiac problems
EP0773038A3 (en) * 1995-11-07 1998-09-23 Telectronics N.V. Improved graphic interface for pacemaker programmers
US5607460A (en) * 1996-03-15 1997-03-04 Angeion Corporation Physician interface expert system for programming implantable arrythmia treatment devices
US5782876A (en) * 1996-04-15 1998-07-21 Medtronic, Inc. Method and apparatus using windows and an index value for identifying cardic arrhythmias
US5891178A (en) * 1996-05-14 1999-04-06 Pacesetter, Inc. Programmer system and associated methods for rapidly evaluating and programming an implanted cardiac device
US6259950B1 (en) 1996-05-14 2001-07-10 Pacesetter, Inc. Implantable stimulation device and method for determining a trial autocapture using backup atrial stimulation
US6263244B1 (en) 1996-05-14 2001-07-17 Pacesetter, Inc. Implantable stimulation device and method for determining atrial autocapture using PVC response
US6594523B1 (en) * 1996-05-14 2003-07-15 Pacesetter, Inc. Implantable stimulation device, programmer, and method for automatically evaluating interaction of the device with a patient's heart
US20030135095A1 (en) * 1996-07-12 2003-07-17 Iliff Edwin C. Computerized medical diagnostic and treatment advice system including network access
US6206829B1 (en) 1996-07-12 2001-03-27 First Opinion Corporation Computerized medical diagnostic and treatment advice system including network access
US6482156B2 (en) 1996-07-12 2002-11-19 First Opinion Corporation Computerized medical diagnostic and treatment advice system including network access
US7344496B2 (en) 1996-07-12 2008-03-18 Clinical Decision Support, Llc Computerized medical diagnostic system utilizing list-based processing
US6849045B2 (en) 1996-07-12 2005-02-01 First Opinion Corporation Computerized medical diagnostic and treatment advice system including network access
US20040059200A1 (en) * 1996-07-12 2004-03-25 Iliff Edwin C. Computerized medical diagnostic system utilizing list-based processing
US5713938A (en) * 1996-11-12 1998-02-03 Pacesetter, Inc. Fuzzy logic expert system for an implantable cardiac device
US5948005A (en) * 1997-01-28 1999-09-07 Pacesetter, Inc. Multi-event bin heart rate histogram for use with and implantable pacemaker
US20080052116A1 (en) * 1997-03-13 2008-02-28 Clinical Decision Support, Llc Disease management system and method
US8740790B2 (en) 1997-03-13 2014-06-03 Clinical Decision Support, Llc Disease management system and method
US7993267B2 (en) 1997-03-13 2011-08-09 Clinical Decision Support, Llc Disease management system including a no response method
US8392217B2 (en) 1997-03-13 2013-03-05 Clinical Decision Support, Llc Disease management system and method including preview mode
US8628470B1 (en) 1997-03-13 2014-01-14 Clinical Decision Support, Llc Disease management system and method including medication therapy self-management
US7769600B2 (en) 1997-03-13 2010-08-03 Clinical Decision Support Disease management system and method
US20080045811A1 (en) * 1997-03-13 2008-02-21 Clinical Decision Support, Llc Disease management system and method including significant symptom filtering
US8663104B2 (en) 1997-03-13 2014-03-04 Clinical Decision Support, Llc Disease management system and method including therapeutic alterations permission level
US8727979B2 (en) 1997-03-13 2014-05-20 Clinical Decision Support, Llc Disease management system and method including significant symptom filtering
US20080052118A1 (en) * 1997-03-13 2008-02-28 Clinical Decision Support, Llc Disease management system and method including permission database
US8682694B2 (en) 1997-03-13 2014-03-25 Clinical Decision Support, Llc Disease management system and method including permission database
US8727976B2 (en) 1997-03-13 2014-05-20 Clinical Decision Support, Llc Disease management system operating on a network
US20080052121A1 (en) * 1997-03-13 2008-02-28 Clinical Decision Support, Llc Disease management system operating on a network
US8060378B2 (en) 1997-03-13 2011-11-15 Clinical Decision Support, Llc Disease management system and method including question version
US8066636B2 (en) 1997-03-13 2011-11-29 Clinical Decision Support, Llc Disease management system and method including pain code
US8630875B2 (en) 1997-03-13 2014-01-14 Clinical Decision Support, Llc Disease management system and health assessment method
US20030074036A1 (en) * 1998-02-06 2003-04-17 Intermedics Inc. Implantable device with digital waveform telemetry
US6959213B2 (en) 1998-02-06 2005-10-25 Intermedics, Inc. Implantable device with digital waveform telemetry
US6301503B1 (en) 1998-03-25 2001-10-09 Cardiac Pacemakers, Inc. System for grouping and displaying cardiac arrhythmia data
US6016442A (en) * 1998-03-25 2000-01-18 Cardiac Pacemakers, Inc. System for displaying cardiac arrhythmia data
US6091990A (en) * 1998-03-25 2000-07-18 Cardiac Pacemakers, Inc. System for grouping and displaying cardiac arrhythmia data
US6253102B1 (en) 1998-03-25 2001-06-26 Cardiac Pacemakers, Inc. System for displaying cardiac arrhythmia data
US6021351A (en) * 1998-05-11 2000-02-01 Cardiac Pacemakers, Inc. Method and apparatus for assessing patient well-being
US6317633B1 (en) 1999-01-19 2001-11-13 Medtronic, Inc. Implantable lead functional status monitor and method
US6684221B1 (en) * 1999-05-06 2004-01-27 Oracle International Corporation Uniform hierarchical information classification and mapping system
US20050159781A1 (en) * 1999-07-14 2005-07-21 Cardiac Pacemakers, Inc. Classification of supraventricular and ventricular cardiac rhythms using cross channel timing algorithm
US8050757B2 (en) 1999-07-14 2011-11-01 Cardiac Pacemakers, Inc. Classification of supraventricular and ventricular cardiac rhythms using cross channel timing algorithm
US20090312811A1 (en) * 1999-07-14 2009-12-17 William Hsu Classification of supraventricular and ventricular cardiac rhythms using cross channel timing algorithm
US7580744B2 (en) 1999-07-14 2009-08-25 Cardiac Pacemakers, Inc. Classification of supraventricular and ventricular cardiac rhythms using cross channel timing algorithm
US8315697B2 (en) 1999-07-14 2012-11-20 Cardiac Pacemakers, Inc. Classification of supraventricular and ventricular cardiac rhythms using cross channel timing algorithm
US20030060849A1 (en) * 1999-07-14 2003-03-27 Cardiac Pacemakers, Inc. Classification of supraventricular and ventricular cardiac rhythms using cross channel timing algorithm
US6889081B2 (en) 1999-07-14 2005-05-03 Cardiac Pacemakers, Inc. Classification of supraventricular and ventricular cardiac rhythms using cross channel timing algorithm
US20090036942A1 (en) * 1999-08-20 2009-02-05 Cardiac Pacemakers, Inc. Method and system for identifying and displaying groups of cardiac arrhythmic episodes
US6289244B1 (en) * 1999-08-20 2001-09-11 Cardiac Pacemakers, Inc. Self audit system
US7200436B2 (en) 1999-08-20 2007-04-03 Cardiac Pacemakers, Inc. Implantable pulse generator and method having adjustable signal blanking
US20040243194A1 (en) * 1999-08-20 2004-12-02 Cardiac Pacemakers, Inc. Implantable pulse generator and method having adjustable signal blanking
US8463369B2 (en) 1999-08-20 2013-06-11 Cardiac Pacemakers, Inc. Arrhythmia display
US6843801B2 (en) 1999-08-20 2005-01-18 Cardiac Pacemakers, Inc. Method and system for identifying and displaying groups of cardiac arrhythmic episodes
US20020151809A1 (en) * 1999-08-20 2002-10-17 Cardiac Pacemakers, Inc. Method and system for identifying and displaying groups of cardiac arrhythmic episodes
US7010349B2 (en) 1999-08-20 2006-03-07 Cardiac Pacemakers, Inc. System and method for detecting and displaying parameter interactions
US6873875B1 (en) 1999-08-20 2005-03-29 Cardiac Pacemakers, Inc. Implantable pulse generator and method having adjustable signal blanking
US8634917B2 (en) 1999-08-20 2014-01-21 Cardiac Pacemakers, Inc. Method and system for identifying and displaying groups of cardiac arrhythmic episodes
US20050107840A1 (en) * 1999-08-20 2005-05-19 Cardiac Pacemakers, Inc. Method and system for identifying and displaying groups of cardiac arrhythmic episodes
US6687539B2 (en) 1999-08-20 2004-02-03 Cardiac Pacemakers, Inc. Implantable defibrillators with programmable cross-chamber blanking
US7418295B2 (en) 1999-08-20 2008-08-26 Cardiac Pacemakers, Inc. Method and system for identifying and displaying groups of cardiac arrhythmic episodes
US7962203B2 (en) 1999-08-20 2011-06-14 Cardiac Pacemakers, Inc. Arrhythmia display
US6304778B1 (en) 1999-08-20 2001-10-16 Cardiac Pacemakers, Inc. Implantable defibrillators with programmable cross-chamber blanking
US20040230232A1 (en) * 1999-08-20 2004-11-18 Cardiac Pacemakers, Inc. Implantable defibrillators with programmable cross-chamber blanking
US20030114891A1 (en) * 1999-08-22 2003-06-19 Cardiac Pacemakers, Inc. Event marker alignment by inclusion of event marker transmission latency in the real-time data stream
US7117037B2 (en) 1999-08-22 2006-10-03 Cardiac Pacemakers, Inc. Event marker alignment by inclusion of event marker transmission latency in the real-time data stream
US6718198B2 (en) 1999-08-24 2004-04-06 Cardiac Pacemakers, Inc. Arrhythmia display
US6721594B2 (en) 1999-08-24 2004-04-13 Cardiac Pacemakers, Inc. Arrythmia display
US6721600B2 (en) 2000-01-19 2004-04-13 Medtronic, Inc. Implantable lead functional status monitor and method
US8019582B2 (en) 2000-02-14 2011-09-13 Clinical Decision Support, Llc Automated diagnostic system and method
US6650944B2 (en) 2000-02-23 2003-11-18 Medtronic, Inc. Follow-up monitoring method and system for implantable medical devices
US6405087B1 (en) 2000-02-25 2002-06-11 Pacesetter, Inc. Cardiac stimulation system providing implantable device performance evaluation and method
WO2002018009A1 (en) 2000-08-26 2002-03-07 Medtronic, Inc. Implantable lead functional status monitor and method
US20070135851A1 (en) * 2000-08-29 2007-06-14 Cardiac Pacemakers, Inc. Implantable pulse generator and method having adjustable signal blanking
US7801606B2 (en) 2000-08-29 2010-09-21 Cardiac Pacemakers, Inc. Implantable pulse generator and method having adjustable signal blanking
US7974692B2 (en) 2000-08-29 2011-07-05 Cardiac Pacemakers, Inc. Implantable pulse generator and method having adjustable signal blanking
US20100324622A1 (en) * 2000-08-29 2010-12-23 Gilkerson James O Implantable pulse generator and method having adjustable signal blanking
US8214037B2 (en) 2000-08-29 2012-07-03 Cardiac Pacemakers, Inc. Implantable pulse generator and method having adjustable signal blanking
US7289845B2 (en) 2000-10-31 2007-10-30 Cardiac Pacemakers, Inc. Curvature based method for selecting features from an electrophysiologic signal for purpose of complex identification and classification
US20040127806A1 (en) * 2000-10-31 2004-07-01 Cardiac Pacemakers, Inc. Curvature based method for selecting features from an electrophysiologic signals for purpose of complex identification and classification
US8725242B2 (en) 2000-12-15 2014-05-13 Cardiac Pacemakers, Inc. System and method for displaying a histogram of cardiac events
US7844322B2 (en) 2000-12-15 2010-11-30 Cardiac Pacemakers, Inc. System and method for correlation of patient health information and implant device data
US20080269827A1 (en) * 2000-12-15 2008-10-30 Cardiac Pacemakers, Inc. System and method for displaying a histogram of cardiac events
US8548576B2 (en) 2000-12-15 2013-10-01 Cardiac Pacemakers, Inc. System and method for correlation of patient health information and implant device data
US7406348B2 (en) 2000-12-15 2008-07-29 Cardiac Pacemakers, Inc. System and method for displaying a histogram of cardiac events
US8818511B2 (en) 2000-12-15 2014-08-26 Cardiac Pacemakers, Inc. Automatic selection of stimulation chamber for ventricular resynchronization therapy
US8032208B2 (en) 2000-12-15 2011-10-04 Cardiac Pacemakers, Inc. System and method for displaying a histogram of cardiac events
US20040082976A1 (en) * 2000-12-15 2004-04-29 Cardiac Pacemakers, Inc. System and method for correlation of patient health information and implant device data
US6665558B2 (en) 2000-12-15 2003-12-16 Cardiac Pacemakers, Inc. System and method for correlation of patient health information and implant device data
US8131351B2 (en) 2000-12-15 2012-03-06 Cardiac Pacemakers, Inc. System and method for correlation of patient health information and implant device data
US8838220B2 (en) 2000-12-15 2014-09-16 Cardiac Pacemakers, Inc. System and method for correlation of patient health information and implant device data
US9061156B2 (en) 2000-12-15 2015-06-23 Cardiac Pacemakers, Inc. Automatic selection of stimulation chamber for ventricular resynchronization therapy
US9949687B2 (en) 2000-12-15 2018-04-24 Cardiac Pacemakers, Inc. System and method for correlation of patient health information and device data
US20050187588A1 (en) * 2000-12-15 2005-08-25 Cardiac Pacemakers, Inc. System and method for displaying cardiac events
US20110046692A1 (en) * 2000-12-15 2011-02-24 James Kalgren System and method for correlation of patient health information and implant device data
US9155904B2 (en) 2000-12-15 2015-10-13 Cardiac Pacemakers, Inc. System and method for correlation of patient health information and implant device data
US9533166B2 (en) 2000-12-15 2017-01-03 Cardiac Pacemakers, Inc. System and method for correlation of patient health information and device data
US20090248104A1 (en) * 2000-12-15 2009-10-01 Jiang Ding Automatic selection of stimulation chamber for ventricular resynchronization therapy
US7047065B2 (en) 2000-12-15 2006-05-16 Cardiac Pacemakers, Inc. System and method for correlation of patient health information and implant device data
US20070250125A1 (en) * 2000-12-26 2007-10-25 Cardiac Pacemakers, Inc. Expert system and method
US7899534B2 (en) 2000-12-26 2011-03-01 Cardiac Pacemakers, Inc. Expert system and method
US8386036B2 (en) 2000-12-26 2013-02-26 Cardiac Pacemakers, Inc. Expert system and method
US7181285B2 (en) 2000-12-26 2007-02-20 Cardiac Pacemakers, Inc. Expert system and method
US8099165B2 (en) 2000-12-26 2012-01-17 Cardiac Pacemakers, Inc. Expert system and method
US20110137368A1 (en) * 2000-12-26 2011-06-09 Par Lindh Expert system and method
US6987998B2 (en) 2001-02-28 2006-01-17 Cardiac Pacemakers, Inc. Cardiac rhythm management patient report
US20020156389A1 (en) * 2001-02-28 2002-10-24 Cardiac Pacemakers, Inc. Cardiac rhythm management patient report
US6668188B2 (en) 2001-04-25 2003-12-23 Cardiac Pacemakers, Inc. Determination of long-term condition of cardiac patients
US7610084B2 (en) 2001-06-05 2009-10-27 Cardiac Pacemakers, Inc. System and method for classifying cardiac depolarization complexes with multi-dimensional correlation
US20060211949A1 (en) * 2001-06-05 2006-09-21 Cardiac Pacemakers, Inc. System and method for classifying cardiac depolarization complexes with multi-dimensional correlation
US20080077031A1 (en) * 2001-11-07 2008-03-27 Cardiac Pacemakers, Inc. System and method for remote expert-system medical device programming
US20030088290A1 (en) * 2001-11-07 2003-05-08 Spinelli Julio C. Centralized management system for programmable medical devices
US7383088B2 (en) 2001-11-07 2008-06-03 Cardiac Pacemakers, Inc. Centralized management system for programmable medical devices
US8755897B2 (en) 2001-11-07 2014-06-17 Cardiac Pacemakers, Inc. System and method for remote expert-system medical device programming
WO2003077822A2 (en) 2001-12-31 2003-09-25 Medtronic,Inc. Imd lead status monitor method and system
US20030171791A1 (en) * 2002-03-06 2003-09-11 Kenknight Bruce H. Method and apparatus for establishing context among events and optimizing implanted medical device performance
US8160716B2 (en) 2002-03-06 2012-04-17 Cardiac Pacemakers, Inc. Method and apparatus for establishing context among events and optimizing implanted medical device performance
US8694116B2 (en) 2002-03-06 2014-04-08 Cardiac Pacemakers, Inc. Method and apparatus for establishing context among events and optimizing implanted medical device performance
US7805199B2 (en) 2002-03-06 2010-09-28 Cardiac Pacemakers, Inc. Method and apparatus for establishing context among events and optimizing implanted medical device performance
US7043305B2 (en) 2002-03-06 2006-05-09 Cardiac Pacemakers, Inc. Method and apparatus for establishing context among events and optimizing implanted medical device performance
US9375566B2 (en) 2002-03-06 2016-06-28 Cardiac Pacemakers, Inc. Device for reporting heart failure status
US10413196B2 (en) 2002-03-06 2019-09-17 Cardiac Pacemakers, Inc. Device for reporting heart failure status
US9480848B2 (en) 2002-03-06 2016-11-01 Cardiac Pacemakers, Inc. Advanced patient management with environmental data
US10092186B2 (en) 2002-03-06 2018-10-09 Cardiac Pacemakers, Inc. Advanced patient management with environmental data
US7113825B2 (en) 2002-05-03 2006-09-26 Cardiac Pacemakers, Inc. Method and apparatus for detecting acoustic oscillations in cardiac rhythm
US20030208240A1 (en) * 2002-05-03 2003-11-06 Pastore Joseph M. Method and apparatus for detecting acoustic oscillations in cardiac rhythm
US20040010200A1 (en) * 2002-07-15 2004-01-15 Sweeney Robert J. Use of curvature based features for beat detection
US6950702B2 (en) 2002-07-15 2005-09-27 Cardiac Pacemakers, Inc. Use of curvature based features for beat detection
US7047083B2 (en) 2002-09-30 2006-05-16 Medtronic, Inc. Method and apparatus for identifying lead-related conditions using lead impedance measurements
US20040064161A1 (en) * 2002-09-30 2004-04-01 Gunderson Bruce D. Method and apparatus for identifying lead-related conditions using lead impedance measurements
US7539536B2 (en) 2002-11-08 2009-05-26 Cardiac Pacemakers, Inc. Cardiac rhythm management systems and methods using multiple morphology templates for discriminating between rhythms
US7031764B2 (en) 2002-11-08 2006-04-18 Cardiac Pacemakers, Inc. Cardiac rhythm management systems and methods using multiple morphology templates for discriminating between rhythms
US20040093035A1 (en) * 2002-11-08 2004-05-13 Mark Schwartz Cardiac rhythm management systems and methods using multiple morphology templates for discriminating between rhythms
US20040111131A1 (en) * 2002-12-05 2004-06-10 Bo Hu Cardiac rhythm management systems and methods for rule-illustrative parameter entry
US7191006B2 (en) 2002-12-05 2007-03-13 Cardiac Pacemakers, Inc. Cardiac rhythm management systems and methods for rule-illustrative parameter entry
US20040219600A1 (en) * 2002-12-13 2004-11-04 Williams Robert Wood Method for determining sensitivity to environmental toxins and susceptibility to parkinson's disease
US20040122485A1 (en) * 2002-12-18 2004-06-24 Stahmann Jeffrey E. Advanced patient management for reporting multiple health-related parameters
US20040122487A1 (en) * 2002-12-18 2004-06-24 John Hatlestad Advanced patient management with composite parameter indices
US8301252B2 (en) 2002-12-18 2012-10-30 Cardiac Pacemakers, Inc. Advanced patient management with composite parameter indices
US20040122294A1 (en) * 2002-12-18 2004-06-24 John Hatlestad Advanced patient management with environmental data
US8043213B2 (en) 2002-12-18 2011-10-25 Cardiac Pacemakers, Inc. Advanced patient management for triaging health-related data using color codes
US7468032B2 (en) 2002-12-18 2008-12-23 Cardiac Pacemakers, Inc. Advanced patient management for identifying, displaying and assisting with correlating health-related data
US20040122486A1 (en) * 2002-12-18 2004-06-24 Stahmann Jeffrey E. Advanced patient management for acquiring, trending and displaying health-related parameters
US20040122297A1 (en) * 2002-12-18 2004-06-24 Stahmann Jeffrey E. Advanced patient management for identifying, displaying and assisting with correlating health-related data
US8391989B2 (en) 2002-12-18 2013-03-05 Cardiac Pacemakers, Inc. Advanced patient management for defining, identifying and using predetermined health-related events
US20040122484A1 (en) * 2002-12-18 2004-06-24 John Hatlestad Advanced patient management for defining, identifying and using predetermined health-related events
US20040122295A1 (en) * 2002-12-18 2004-06-24 John Hatlestad Advanced patient management for triaging health-related data using color codes
US7959568B2 (en) 2002-12-18 2011-06-14 Cardiac Pacemakers, Inc. Advanced patient management for identifying, displaying and assisting with correlating health-related data
US8543215B2 (en) 2002-12-18 2013-09-24 Cardiac Pacemakers, Inc. Advanced patient management for defining, identifying and using predetermined health-related events
US8639318B2 (en) 2002-12-18 2014-01-28 Cardiac Pacemakers, Inc. Advanced patient management with composite parameter indices
US7983759B2 (en) 2002-12-18 2011-07-19 Cardiac Pacemakers, Inc. Advanced patient management for reporting multiple health-related parameters
US7983745B2 (en) 2002-12-18 2011-07-19 Cardiac Pacemakers, Inc. Advanced patient management with environmental data
US20060135855A1 (en) * 2002-12-20 2006-06-22 Koninklijke Philips Electronics N.V. Method for determining normal measurements for a patient
US20040127792A1 (en) * 2002-12-30 2004-07-01 Siejko Krzysztof Z. Method and apparatus for monitoring of diastolic hemodynamics
US20110098588A1 (en) * 2002-12-30 2011-04-28 Siejko Krzysztof Z Method and apparatus for monitoring of diastolic hemodynamics
US7972275B2 (en) 2002-12-30 2011-07-05 Cardiac Pacemakers, Inc. Method and apparatus for monitoring of diastolic hemodynamics
US8636669B2 (en) 2002-12-30 2014-01-28 Cardiac Pacemakers, Inc. Method and apparatus for monitoring of diastolic hemodynamics
US6980850B1 (en) * 2002-12-30 2005-12-27 Pacesetter, Inc. System and method for emulating a surface EKG using an implantable cardiac stimulation device
US6993379B1 (en) 2002-12-30 2006-01-31 Pacesetter, Inc. System and method for emulating a surface EKG using an implantable cardiac stimulation device
US8027725B2 (en) 2002-12-31 2011-09-27 Cardiac Pacemakers, Inc. Capture verification using an evoked response reference
US20070156196A1 (en) * 2002-12-31 2007-07-05 Cardiac Pacemakers, Inc. Capture verification using an evoked response reference
US7702393B2 (en) * 2002-12-31 2010-04-20 Cardiac Pacemakers, Inc. Method and system for detecting capture with cancellation of pacing artifact
US7676267B2 (en) 2002-12-31 2010-03-09 Cardiac Pacemakers, Inc. Capture verification using an evoked response reference
US20070129766A1 (en) * 2002-12-31 2007-06-07 Cardiac Pacemakers, Inc. Method and system for detecting capture with cancellation of pacing artifact
US7191004B2 (en) 2002-12-31 2007-03-13 Cardiac Pacemakers, Inc. Capture verification using an evoked response reference
US20040127949A1 (en) * 2002-12-31 2004-07-01 Jaeho Kim Method and system for detecting capture with cancellation of pacing artifact
US20040127950A1 (en) * 2002-12-31 2004-07-01 Jaeho Kim Capture verification using an evoked response reference
US7162301B2 (en) * 2002-12-31 2007-01-09 Cardiac Pacemakers, Inc. Method and system for detecting capture with cancellation of pacing artifact
US8050762B2 (en) 2002-12-31 2011-11-01 Jaeho Kim Method and system for detecting capture with cancellation of pacing artifact
US20100168814A1 (en) * 2002-12-31 2010-07-01 Jaeho Kim Method and System for Detecting Capture with Cancellation of Pacing Artifact
US7136707B2 (en) 2003-01-21 2006-11-14 Cardiac Pacemakers, Inc. Recordable macros for pacemaker follow-up
US8417350B2 (en) 2003-01-21 2013-04-09 Cardiac Pacemakers, Inc. Recordable macros for pacemaker follow-up
US20040143304A1 (en) * 2003-01-21 2004-07-22 Hall Jeffrey A. Recordable macros for pacemaker follow-up
US8280518B2 (en) 2003-01-21 2012-10-02 Cardiac Pacemakers, Inc. Recordable macros for pacemaker follow-up
US7751892B2 (en) 2003-05-07 2010-07-06 Cardiac Pacemakers, Inc. Implantable medical device programming apparatus having a graphical user interface
US20100249868A1 (en) * 2003-05-07 2010-09-30 Les Norman Peterson Implantable medical device programming apparatus having a graphical user interface
US20050033385A1 (en) * 2003-05-07 2005-02-10 Peterson Les Norman Implantable medical device programming apparatus having a graphical user interface
US20040230456A1 (en) * 2003-05-14 2004-11-18 Lozier Luke R. System for identifying candidates for ICD implantation
US8731968B1 (en) 2003-05-15 2014-05-20 Clinical Decision Support, Llc Panel diagnostic method and system including automated diagnostic analysis
US7780595B2 (en) 2003-05-15 2010-08-24 Clinical Decision Support, Llc Panel diagnostic method and system
US8055516B2 (en) 2003-05-15 2011-11-08 Clinical Decision Support, Llc Panel diagnostic method and system
US8301467B2 (en) 2003-05-15 2012-10-30 Clinical Decision Support, Llc Panel diagnostic method and system including active and passive strategies
US20040252078A1 (en) * 2003-06-13 2004-12-16 Fischer Jonathan H. Bi-directional interface for low data rate application
US20090192395A1 (en) * 2003-06-27 2009-07-30 Sweeney Robert J Signal compression based on curvature parameters
US7792571B2 (en) 2003-06-27 2010-09-07 Cardiac Pacemakers, Inc. Tachyarrhythmia detection and discrimination based on curvature parameters
US8409107B2 (en) 2003-06-27 2013-04-02 Cardiac Pacemakers, Inc. Tachyarrhythmia detection and discrimination based on curvature parameters
US20070203419A1 (en) * 2003-06-27 2007-08-30 Caridac Pacemakers, Inc. Tachyarrhythmia detection and discrimination based on curvature parameters
US7500955B2 (en) 2003-06-27 2009-03-10 Cardiac Pacemaker, Inc. Signal compression based on curvature parameters
US8280508B2 (en) 2003-06-27 2012-10-02 Cardiac Pacemakers, Inc. Signal compression based on curvature parameters
US7286872B2 (en) 2003-10-07 2007-10-23 Cardiac Pacemakers, Inc. Method and apparatus for managing data from multiple sensing channels
US20060058850A1 (en) * 2003-10-07 2006-03-16 Kramer Karen M Method and apparatus for managing data from multiple sensing channels
WO2005056109A1 (en) * 2003-12-04 2005-06-23 Medtronic, Inc. Method and apparatus for identifying lead-related conditions using impedance trends and oversensing criteria
US7289851B2 (en) 2003-12-04 2007-10-30 Medtronic, Inc. Method and apparatus for identifying lead-related conditions using impedance trends and oversensing criteria
US20050137636A1 (en) * 2003-12-04 2005-06-23 Gunderson Bruce D. Method and apparatus for identifying lead-related conditions using impedance trends and oversensing criteria
US7471980B2 (en) 2003-12-22 2008-12-30 Cardiac Pacemakers, Inc. Synchronizing continuous signals and discrete events for an implantable medical device
US20050137627A1 (en) * 2003-12-22 2005-06-23 Koshiol Allan T. Synchronizing continuous signals and discrete events for an implantable medical device
US20060025830A1 (en) * 2004-07-30 2006-02-02 Scott Freeberg Wireless pacing systems analyzer in a programmer system
US7418296B2 (en) 2004-07-30 2008-08-26 Cardiac Pacemakers, Inc. Wireless pacing system analyzer in a programmer system
US9081879B2 (en) 2004-10-22 2015-07-14 Clinical Decision Support, Llc Matrix interface for medical diagnostic and treatment advice system and method
US20060111643A1 (en) * 2004-11-23 2006-05-25 Shelley Cazares Arrhythmia memory for tachyarrhythmia discrimination
US7277747B2 (en) 2004-11-23 2007-10-02 Cardiac Pacemakers, Inc. Arrhythmia memory for tachyarrhythmia discrimination
US7515961B2 (en) 2005-04-29 2009-04-07 Medtronic, Inc. Method and apparatus for dynamically monitoring, detecting and diagnosing lead conditions
WO2006118762A1 (en) 2005-04-29 2006-11-09 Medtronic. Inc. Method and apparatus for dynamically monitoring, detecting and diagnosing lead conditions
US20060247706A1 (en) * 2005-04-29 2006-11-02 Germanson Nancy M Method and apparatus for dynamically monitoring, detecting and diagnosing lead conditions
US8560056B1 (en) 2005-09-12 2013-10-15 Pacesetter, Inc. Intracardiac device and method for storing cardiac test results and associated EGM data
US8260407B1 (en) 2005-09-12 2012-09-04 Pacesetter, Inc. Intracardiac device and method for storing cardiac test results and associated EGM data
US8583219B1 (en) 2005-09-12 2013-11-12 Pacesetter, Inc. Intracardiac device and method for storing cardiac test results and associated EGM data
US8046060B2 (en) 2005-11-14 2011-10-25 Cardiac Pacemakers, Inc. Differentiating arrhythmic events having different origins
US8108034B2 (en) 2005-11-28 2012-01-31 Cardiac Pacemakers, Inc. Systems and methods for valvular regurgitation detection
US8738560B2 (en) 2006-04-27 2014-05-27 Cardiac Pacemakers, Inc. Systems and methods for automatically resolving interaction between programmable parameters
US8321366B2 (en) 2006-04-27 2012-11-27 Cardiac Pacemakers, Inc. Systems and methods for automatically resolving interaction between programmable parameters
US20100016996A1 (en) * 2006-04-27 2010-01-21 Jeff West Medical device user interface automatically resolving interaction between programmable parameters
US7979378B2 (en) 2006-04-27 2011-07-12 Cardiac Pacemakers, Inc. Medical device user interface automatically resolving interaction between programmable parameters
US20080021287A1 (en) * 2006-06-26 2008-01-24 Woellenstein Matthias D System and method for adaptively adjusting patient data collection in an automated patient management environment
US20080103744A1 (en) * 2006-10-25 2008-05-01 Ai Medical Semiconductor Heart Simulator
US7963924B2 (en) * 2006-10-25 2011-06-21 Sorin Crm Sas Heart simulator
US20080103552A1 (en) * 2006-10-31 2008-05-01 Medtronic, Inc. Controller for obtaining prescriptive analysis of functionality of implantable medical device leads, system and method therefore
US20090259216A1 (en) * 2008-04-10 2009-10-15 Medtronic, Inc. Automated integrity tests
US8287520B2 (en) 2008-04-10 2012-10-16 Medtronic, Inc. Automated integrity tests
US8644931B2 (en) 2008-06-02 2014-02-04 Medtronic, Inc. Impedance variability analysis to identify lead-related conditions
US20090299429A1 (en) * 2008-06-02 2009-12-03 Medtronic, Inc. Sensing integrity determination based on cardiovascular pressure
US20090299201A1 (en) * 2008-06-02 2009-12-03 Medtronic, Inc. Electrode lead integrity reports
US9037240B2 (en) 2008-06-02 2015-05-19 Medtronic, Inc. Electrode lead integrity reports
US8126553B2 (en) 2008-06-02 2012-02-28 Medtronic, Inc. Sensing integrity determination based on cardiovascular pressure
US8200322B2 (en) 2008-06-02 2012-06-12 Medtronic, Inc. Electrogram storage for suspected non-physiological episodes
US20090299422A1 (en) * 2008-06-02 2009-12-03 Medtronic, Inc. Electrogram storage for suspected non-physiological episodes
US20090299421A1 (en) * 2008-06-02 2009-12-03 Medtronic, Inc. Evaluation of implantable medical device sensing integrity based on evoked signals
US20090299432A1 (en) * 2008-06-02 2009-12-03 Metronic, Inc. Impedance variability analysis to identify lead-related conditions
US20090326600A1 (en) * 2008-06-30 2009-12-31 Medtronic, Inc. Lead integrity testing during suspected tachyarrhythmias
US7974690B2 (en) 2008-06-30 2011-07-05 Medtronic, Inc. Lead integrity testing during suspected tachyarrhythmias
US9522277B2 (en) 2008-07-28 2016-12-20 Medtronic, Inc. Lead integrity testing triggered by sensed signal saturation
US7953488B2 (en) 2008-07-31 2011-05-31 Medtronic, Inc. Pre-qualification of an alternate sensing configuration
US20100030289A1 (en) * 2008-07-31 2010-02-04 Medtronic, Inc. Pre-qualification of an alternate sensing configuration
US8781585B2 (en) 2008-10-29 2014-07-15 Medtronic, Inc. Identification and remediation of oversensed cardiac events using far-field electrograms
US8078277B2 (en) 2008-10-29 2011-12-13 Medtronic, Inc. Identification and remediation of oversensed cardiac events using far-field electrograms
US20100106209A1 (en) * 2008-10-29 2010-04-29 Medtronic, Inc. Identification and remediation of oversensed cardiac events using far-field electrograms
US10118042B2 (en) 2008-10-31 2018-11-06 Medtronic, Inc. Lead integrity testing triggered by sensed asystole
US20100191544A1 (en) * 2009-01-27 2010-07-29 Adam Bosworth Protocol Authoring for a Health Coaching Service
US20100280838A1 (en) * 2009-05-01 2010-11-04 Adam Bosworth Coaching Engine for a Health Coaching Service
US9211096B2 (en) 2009-10-08 2015-12-15 The Regents Of The University Of Michigan Real time clinical decision support system having medical systems as display elements
US8936555B2 (en) 2009-10-08 2015-01-20 The Regents Of The University Of Michigan Real time clinical decision support system having linked references
US9378335B2 (en) 2009-11-23 2016-06-28 Keas, Inc. Risk factor engine that determines a user health score using a food consumption trend, and predicted user weights
US8396543B2 (en) 2010-01-28 2013-03-12 Medtronic, Inc. Storage of data for evaluation of lead integrity
US20110184481A1 (en) * 2010-01-28 2011-07-28 Medtronic, Inc. Storage of data for evaluation of lead integrity
US8600504B2 (en) 2010-07-02 2013-12-03 Cardiac Pacemakers, Inc. Physiologic demand driven pacing
US8774909B2 (en) 2011-09-26 2014-07-08 Medtronic, Inc. Episode classifier algorithm
US8437840B2 (en) 2011-09-26 2013-05-07 Medtronic, Inc. Episode classifier algorithm
US8744560B2 (en) 2011-09-30 2014-06-03 Medtronic, Inc. Electrogram summary
US9668668B2 (en) 2011-09-30 2017-06-06 Medtronic, Inc. Electrogram summary
US8886296B2 (en) 2011-10-14 2014-11-11 Medtronic, Inc. T-wave oversensing
US8521281B2 (en) 2011-10-14 2013-08-27 Medtronic, Inc. Electrogram classification algorithm
US9839784B2 (en) 2012-05-08 2017-12-12 Medtronic, Inc. Identifying lead insulation breaches and externalization of lead conductors
US9956417B2 (en) 2012-05-08 2018-05-01 Medtronic, Inc. Identifying lead insulation breaches and externalization of lead conductors
US9399141B2 (en) 2014-02-13 2016-07-26 Medtronic, Inc. Lead monitoring frequency based on lead and patient characteristics
US9409026B2 (en) 2014-02-13 2016-08-09 Medtronic, Inc. Lead monitoring frequency based on lead and patient characteristics
WO2015123483A1 (en) 2014-02-13 2015-08-20 Medtronic, Inc. Lead monitoring frequency based on lead and patient characteristics
US9302100B2 (en) 2014-02-13 2016-04-05 Medtronic, Inc. Lead monitoring frequency based on lead and patient characteristics

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